[One (M8) Original Android Development] dthomasen:
I get it too. Bluetooth switching off after about 2 hours of use and refuses to turn on again (Android Wear - LG G Watch R).

Seems like the bluetooth service is unregistered..

Logcat:

06-09 19:41:19.357 1053-14233/com.android.systemui D/BluetoothA2dpSink﹕ onBluetoothStateChange: up=false
06-09 19:41:19.369 1053-14233/com.android.systemui E/BluetoothA2dpSink﹕ java.lang.IllegalArgumentException: Service not registered: android.bluetooth.BluetoothA2dpSink$2@24f1bd19
at android.app.LoadedApk.forgetServiceDispatcher(LoadedApk.java:1029)
at android.app.ContextImpl.unbindService(ContextImpl.java:1825)
at android.content.ContextWrapper.unbindService(ContextWrapper.java:551)
at android.bluetooth.BluetoothA2dpSink$1.onBluetoothStateChange(BluetoothA2dpSink.java:139)
at android.bluetooth.IBluetoothStateChangeCallback$Stub.onTransact(IBluetoothStateChangeCallback.java:55)
at android.os.Binder.execTransact(Binder.java:446)
06-09 19:41:19.371 1053-1087/com.android.systemui D/BluetoothAvrcpController﹕ onBluetoothStateChange: up=false
06-09 19:41:19.371 1053-1087/com.android.systemui E/BluetoothAvrcpController﹕ java.lang.IllegalArgumentException: Service not registered: android.bluetooth.BluetoothAvrcpController$2@3ce151de
at android.app.LoadedApk.forgetServiceDispatcher(LoadedApk.java:1029)
at android.app.ContextImpl.unbindService(ContextImpl.java:1825)
at android.content.ContextWrapper.unbindService(ContextWrapper.java:551)
at android.bluetooth.BluetoothAvrcpController$1.onBluetoothStateChange(BluetoothAvrcpController.java:80)
at android.bluetooth.IBluetoothStateChangeCallback$Stub.onTransact(IBluetoothStateChangeCallback.java:55)
at android.os.Binder.execTransact(Binder.java:446)
06-09 19:41:19.372 1053-2206/com.android.systemui D/BluetoothPan﹕ onBluetoothStateChange on: false
06-09 19:41:19.372 1053-2206/com.android.systemui E/BluetoothPan﹕ java.lang.IllegalArgumentException: Service not registered: android.bluetooth.BluetoothPan$2@ee2b05f
at android.app.LoadedApk.forgetServiceDispatcher(LoadedApk.java:1029)
at android.app.ContextImpl.unbindService(ContextImpl.java:1825)
at android.content.ContextWrapper.unbindService(ContextWrapper.java:551)
at android.bluetooth.BluetoothPan$1.onBluetoothStateChange(BluetoothPan.java:206)
at android.bluetooth.IBluetoothStateChangeCallback$Stub.onTransact(IBluetoothStateChangeCallback.java:55)
at android.os.Binder.execTransact(Binder.java:446)
06-09 19:41:19.373 1053-13037/com.android.systemui D/BluetoothInputDevice﹕ onBluetoothStateChange: up=false
06-09 19:41:19.373 1053-13037/com.android.systemui E/BluetoothInputDevice﹕ java.lang.IllegalArgumentException: Service not registered: android.bluetooth.BluetoothInputDevice$2@271464b9
at android.app.LoadedApk.forgetServiceDispatcher(LoadedApk.java:1029)
at android.app.ContextImpl.unbindService(ContextImpl.java:1825)
at android.content.ContextWrapper.unbindService(ContextWrapper.java:551)
at android.bluetooth.BluetoothInputDevice$1.onBluetoothStateChange(BluetoothInputDevice.java:227)
at android.bluetooth.IBluetoothStateChangeCallback$Stub.onTransact(IBluetoothStateChangeCallback.java:55)
at android.os.Binder.execTransact(Binder.java:446)
06-09 19:41:19.374 1053-1089/com.android.systemui D/BluetoothHeadsetClient﹕ onBluetoothStateChange: up=false
06-09 19:41:19.375 1053-1089/com.android.systemui E/BluetoothHeadsetClient﹕ java.lang.IllegalArgumentException: Service not registered: android.bluetooth.BluetoothHeadsetClient$2@295afbf
at android.app.LoadedApk.forgetServiceDispatcher(LoadedApk.java:1029)
at android.app.ContextImpl.unbindService(ContextImpl.java:1825)
at android.content.ContextWrapper.unbindService(ContextWrapper.java:551)
at android.bluetooth.BluetoothHeadsetClient$1.onBluetoothStateChange(BluetoothHeadsetClient.java:382)
at android.bluetooth.IBluetoothStateChangeCallback$Stub.onTransact(IBluetoothStateChangeCallback.java:55)
at android.os.Binder.execTransact(Binder.java:446)
06-09 19:41:19.376 1053-14233/com.android.systemui D/BluetoothA2dp﹕ onBluetoothStateChange: up=false
06-09 19:41:19.376 1053-14233/com.android.systemui E/BluetoothA2dp﹕ java.lang.IllegalArgumentException: Service not registered: android.bluetooth.BluetoothA2dp$2@27aa3680
at android.app.LoadedApk.forgetServiceDispatcher(LoadedApk.java:1029)
at android.app.ContextImpl.unbindService(ContextImpl.java:1825)
at android.content.ContextWrapper.unbindService(ContextWrapper.java:551)
at android.bluetooth.BluetoothA2dp$1.onBluetoothStateChange(BluetoothA2dp.java:126)
at android.bluetooth.IBluetoothStateChangeCallback$Stub.onTransact(IBluetoothStateChangeCallback.java:55)
at android.os.Binder.execTransact(Binder.java:446)
06-09 19:41:19.382 1053-1087/com.android.systemui D/BluetoothHeadset﹕ onBluetoothStateChange: up=false
06-09 19:41:19.383 1053-2206/com.android.systemui D/BluetoothMap﹕ onBluetoothStateChange: up=false
06-09 19:41:19.383 1053-2206/com.android.systemui E/BluetoothMap﹕ java.lang.IllegalArgumentException: Service not registered: android.bluetooth.BluetoothMap$2@3a7570fe
at android.app.LoadedApk.forgetServiceDispatcher(LoadedApk.java:1029)
at android.app.ContextImpl.unbindService(ContextImpl.java:1825)
at android.content.ContextWrapper.unbindService(ContextWrapper.java:551)
at android.bluetooth.BluetoothMap$1.onBluetoothStateChange(BluetoothMap.java:64)
at android.bluetooth.IBluetoothStateChangeCallback$Stub.onTransact(IBluetoothStateChangeCallback.java:55)
at android.os.Binder.execTransact(Binder.java:446)

Let me know if you need me to do anything. I'm maintaining an AOSP rom for a custom set top box as a job. :)

EDIT: Clearing data for the app "Bluetooth Share" in settings, fixes the issue.. Will see how long it takes until it happens again.. :)