[OnePlus 3T ROMs, Kernels, Recoveries, & Other Deve] tsubus:
I know you said bluetooth issues cannot be caused by your kernel, but it definitely is causing issues for me. I'm on stock OOS 3.5.4, everything is fine with stock kernel. Just flashed franco kernel r4 (but I had the same issue with r3) and bluetooth doesn't even turn on. The only other "modification" was installing SuperSU (but that was flashed with stock kernel as well), everything else is stock. Here is a logcat (tried to turn on from QS tile):

12-22 12:19:41.268 1969 2591 E BluetoothAdapter:
12-22 12:19:41.268 1969 2591 E BluetoothAdapter: android.os.DeadObjectException
12-22 12:19:41.268 1969 2591 E BluetoothAdapter: at android.os.BinderProxy.transactNative(Native Method)
12-22 12:19:41.268 1969 2591 E BluetoothAdapter: at android.os.BinderProxy.transact(Binder.java:536)
12-22 12:19:41.268 1969 2591 E BluetoothAdapter: at android.bluetooth.IBluetooth$Stub$Proxy.isEnabled(IBluetooth.java:887)
12-22 12:19:41.268 1969 2591 E BluetoothAdapter: at android.bluetooth.BluetoothAdapter.isEnabled(BluetoothAdapter.java:616)
12-22 12:19:41.268 1969 2591 E BluetoothAdapter: at android.bluetooth.BluetoothAdapter.enable(BluetoothAdapter.java:903)
12-22 12:19:41.268 1969 2591 E BluetoothAdapter: at com.android.settingslib.bluetooth.LocalBluetoothAdapter.setBluetoothEnabled(LocalBluetoothAdapter.java:217)
12-22 12:19:41.268 1969 2591 E BluetoothAdapter: at com.android.systemui.statusbar.policy.BluetoothControllerImpl.setBluetoothEnabled(BluetoothControllerImpl.java:126)
12-22 12:19:41.268 1969 2591 E BluetoothAdapter: at com.android.systemui.qs.tiles.BluetoothTile.handleClick(BluetoothTile.java:75)
12-22 12:19:41.268 1969 2591 E BluetoothAdapter: at com.android.systemui.qs.QSTile$H.handleMessage(QSTile.java:318)
12-22 12:19:41.268 1969 2591 E BluetoothAdapter: at android.os.Handler.dispatchMessage(Handler.java:102)
12-22 12:19:41.268 1969 2591 E BluetoothAdapter: at android.os.Looper.loop(Looper.java:148)
12-22 12:19:41.268 1969 2591 E BluetoothAdapter: at android.os.HandlerThread.run(HandlerThread.java:61)
12-22 12:19:41.269 1969 2591 E BluetoothAdapter:
12-22 12:19:41.269 1969 2591 E BluetoothAdapter: android.os.DeadObjectException
12-22 12:19:41.269 1969 2591 E BluetoothAdapter: at android.os.BinderProxy.transactNative(Native Method)
12-22 12:19:41.269 1969 2591 E BluetoothAdapter: at android.os.BinderProxy.transact(Binder.java:536)
12-22 12:19:41.269 1969 2591 E BluetoothAdapter: at android.bluetooth.IBluetooth$Stub$Proxy.getState(IBluetooth.java:904)
12-22 12:19:41.269 1969 2591 E BluetoothAdapter: at android.bluetooth.BluetoothAdapter.enable(BluetoothAdapter.java:910)
12-22 12:19:41.269 1969 2591 E BluetoothAdapter: at com.android.settingslib.bluetooth.LocalBluetoothAdapter.setBluetoothEnabled(LocalBluetoothAdapter.java:217)
12-22 12:19:41.269 1969 2591 E BluetoothAdapter: at com.android.systemui.statusbar.policy.BluetoothControllerImpl.setBluetoothEnabled(BluetoothControllerImpl.java:126)
12-22 12:19:41.269 1969 2591 E BluetoothAdapter: at com.android.systemui.qs.tiles.BluetoothTile.handleClick(BluetoothTile.java:75)
12-22 12:19:41.269 1969 2591 E BluetoothAdapter: at com.android.systemui.qs.QSTile$H.handleMessage(QSTile.java:318)
12-22 12:19:41.269 1969 2591 E BluetoothAdapter: at android.os.Handler.dispatchMessage(Handler.java:102)
12-22 12:19:41.269 1969 2591 E BluetoothAdapter: at android.os.Looper.loop(Looper.java:148)
12-22 12:19:41.269 1969 2591 E BluetoothAdapter: at android.os.HandlerThread.run(HandlerThread.java:61)
12-22 12:19:41.270 1525 2458 D BluetoothManagerService: checkIfCallerIsForegroundUser: valid=true callingUser=0 parentUser=-10000 foregroundUser=0
12-22 12:19:41.270 1525 2458 D BluetoothManagerService: enable(): mBluetooth =android.bluetooth.IBluetooth$Stub$Proxy@927b866 mBinding = false
12-22 12:19:41.270 1525 2458 D BluetoothManagerService: enable returning
12-22 12:19:41.270 1525 1578 D BluetoothManagerService: Message: 1
12-22 12:19:41.270 1525 1578 D BluetoothManagerService: MESSAGE_ENABLE: mBluetooth = android.bluetooth.IBluetooth$Stub$Proxy@927b866
12-22 12:19:41.271 1525 1578 E BluetoothManagerService: Unable to call enable()
12-22 12:19:41.271 1525 1578 E BluetoothManagerService: android.os.DeadObjectException
12-22 12:19:41.271 1525 1578 E BluetoothManagerService: at android.os.BinderProxy.transactNative(Native Method)
12-22 12:19:41.271 1525 1578 E BluetoothManagerService: at android.os.BinderProxy.transact(Binder.java:536)
12-22 12:19:41.271 1525 1578 E BluetoothManagerService: at android.bluetooth.IBluetooth$Stub$Proxy.enable(IBluetooth.java:921)
12-22 12:19:41.271 1525 1578 E BluetoothManagerService: at com.android.server.BluetoothManagerService.handleEnable(BluetoothManagerService.java:1356)
12-22 12:19:41.271 1525 1578 E BluetoothManagerService: at com.android.server.BluetoothManagerService.access$1900(BluetoothManagerService.java:61)
12-22 12:19:41.271 1525 1578 E BluetoothManagerService: at com.android.server.BluetoothManagerService$BluetoothHandler.handleMessage(BluetoothManagerService.java:1020)
12-22 12:19:41.271 1525 1578 E BluetoothManagerService: at android.os.Handler.dispatchMessage(Handler.java:102)
12-22 12:19:41.271 1525 1578 E BluetoothManagerService: at android.os.Looper.loop(Looper.java:148)
12-22 12:19:41.271 1525 1578 E BluetoothManagerService: at android.os.HandlerThread.run(HandlerThread.java:61)
12-22 12:19:41.271 1525 1578 E BluetoothManagerService: at com.android.server.ServiceThread.run(ServiceThread.java:46)

This if I try to turn it on from Settings:

12-22 12:24:13.162 9396 9396 E BluetoothAdapter:
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: android.os.DeadObjectException
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at android.os.BinderProxy.transactNative(Native Method)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at android.os.BinderProxy.transact(Binder.java:536)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at android.bluetooth.IBluetooth$Stub$Proxy.isEnabled(IBluetooth.java:887)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at android.bluetooth.BluetoothAdapter.isEnabled(BluetoothAdapter.java:616)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at android.bluetooth.BluetoothAdapter.enable(BluetoothAdapter.java:903)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at com.android.settingslib.bluetooth.LocalBluetoothAdapter.setBluetoothEnabled(LocalBluetoothAdapter.java:217)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at com.android.settings.bluetooth.BluetoothEnabler.onSwitchChanged(BluetoothEnabler.java:192)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at com.android.settings.widget.SwitchBar.propagateChecked(SwitchBar.java:197)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at com.android.settings.widget.SwitchBar.onCheckedChanged(SwitchBar.java:203)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at android.widget.CompoundButton.setChecked(CompoundButton.java:156)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at android.widget.Switch.setChecked(Switch.java:1070)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at com.android.settings.widget.ToggleSwitch.setChecked(ToggleSwitch.java:57)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at android.widget.Switch.toggle(Switch.java:1065)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at android.widget.CompoundButton.performClick(CompoundButton.java:120)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at android.view.View$PerformClick.run(View.java:21230)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at android.os.Handler.handleCallback(Handler.java:739)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at android.os.Handler.dispatchMessage(Handler.java:95)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at android.os.Looper.loop(Looper.java:148)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at android.app.ActivityThread.main(ActivityThread.java:5507)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at java.lang.reflect.Method.invoke(Native Method)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter:
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: android.os.DeadObjectException
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at android.os.BinderProxy.transactNative(Native Method)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at android.os.BinderProxy.transact(Binder.java:536)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at android.bluetooth.IBluetooth$Stub$Proxy.getState(IBluetooth.java:904)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at android.bluetooth.BluetoothAdapter.enable(BluetoothAdapter.java:910)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at com.android.settingslib.bluetooth.LocalBluetoothAdapter.setBluetoothEnabled(LocalBluetoothAdapter.java:217)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at com.android.settings.bluetooth.BluetoothEnabler.onSwitchChanged(BluetoothEnabler.java:192)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at com.android.settings.widget.SwitchBar.propagateChecked(SwitchBar.java:197)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at com.android.settings.widget.SwitchBar.onCheckedChanged(SwitchBar.java:203)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at android.widget.CompoundButton.setChecked(CompoundButton.java:156)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at android.widget.Switch.setChecked(Switch.java:1070)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at com.android.settings.widget.ToggleSwitch.setChecked(ToggleSwitch.java:57)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at android.widget.Switch.toggle(Switch.java:1065)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at android.widget.CompoundButton.performClick(CompoundButton.java:120)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at android.view.View$PerformClick.run(View.java:21230)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at android.os.Handler.handleCallback(Handler.java:739)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at android.os.Handler.dispatchMessage(Handler.java:95)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at android.os.Looper.loop(Looper.java:148)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at android.app.ActivityThread.main(ActivityThread.java:5507)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at java.lang.reflect.Method.invoke(Native Method)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
12-22 12:24:13.162 9396 9396 E BluetoothAdapter: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
12-22 12:24:13.162 1525 2404 D BluetoothManagerService: enable(): mBluetooth =android.bluetooth.IBluetooth$Stub$Proxy@927b866 mBinding = false
12-22 12:24:13.163 1525 2404 D BluetoothManagerService: enable returning
12-22 12:24:13.163 1525 1578 D BluetoothManagerService: Message: 1
12-22 12:24:13.163 1525 1578 D BluetoothManagerService: MESSAGE_ENABLE: mBluetooth = android.bluetooth.IBluetooth$Stub$Proxy@927b866
12-22 12:24:13.163 1525 1578 E BluetoothManagerService: Unable to call enable()
12-22 12:24:13.163 1525 1578 E BluetoothManagerService: android.os.DeadObjectException
12-22 12:24:13.163 1525 1578 E BluetoothManagerService: at android.os.BinderProxy.transactNative(Native Method)
12-22 12:24:13.163 1525 1578 E BluetoothManagerService: at android.os.BinderProxy.transact(Binder.java:536)
12-22 12:24:13.163 1525 1578 E BluetoothManagerService: at android.bluetooth.IBluetooth$Stub$Proxy.enable(IBluetooth.java:921)
12-22 12:24:13.163 1525 1578 E BluetoothManagerService: at com.android.server.BluetoothManagerService.handleEnable(BluetoothManagerService.java:1356)
12-22 12:24:13.163 1525 1578 E BluetoothManagerService: at com.android.server.BluetoothManagerService.access$1900(BluetoothManagerService.java:61)
12-22 12:24:13.163 1525 1578 E BluetoothManagerService: at com.android.server.BluetoothManagerService$BluetoothHandler.handleMessage(BluetoothManagerService.java:1020)
12-22 12:24:13.163 1525 1578 E BluetoothManagerService: at android.os.Handler.dispatchMessage(Handler.java:102)
12-22 12:24:13.163 1525 1578 E BluetoothManagerService: at android.os.Looper.loop(Looper.java:148)
12-22 12:24:13.163 1525 1578 E BluetoothManagerService: at android.os.HandlerThread.run(HandlerThread.java:61)
12-22 12:24:13.163 1525 1578 E BluetoothManagerService: at com.android.server.ServiceThread.run(ServiceThread.java:46)