[Xiaomi Mi 8 ROMs, Kernels, Recoveries, & Other Dev] hypern0va:
So, to me this seems to be what causes soft reboots to happen:

06-13 16:22:32.882 D/AnyMotionDetector(12159): angleBetween: this = timeMillisSinceBoot=104458649 | x=0.028453069, y=-0.006145332, z=0.9995763, other = timeMillisSinceBoot=104466183 | x=0.028650487, y=-0.006066124, z=0.99957114, degrees = 0.012191183
06-13 16:32:13.495 W/BroadcastQueue(12159): Background execution not allowed: receiving Intent { act=android.net.wifi.STATE_CHANGE flg=0x4000010 (has extras) } to com.here.app.maps/com.here.app.trafficprobegen.WifiIntentReceiver
06-13 16:32:13.500 D/ConnectivityService(12159): NetworkAgentInfo [WIFI () - 104] EVENT_NETWORK_INFO_CHANGED, going from CONNECTED to DISCONNECTED
06-13 16:32:13.500 D/ConnectivityService(12159): NetworkAgentInfo [WIFI () - 104] got DISCONNECTED, was satisfying 15
06-13 16:32:13.506 W/BroadcastQueue(12159): Background execution not allowed: receiving Intent { act=android.net.wifi.STATE_CHANGE flg=0x4000010 (has extras) } to com.here.app.maps/com.here.app.trafficprobegen.WifiIntentReceiver
06-13 16:32:13.508 I/wificond(12081): Pno scan started
06-13 16:32:13.561 D/ConnectivityService(12159): Sending DISCONNECTED broadcast for type 1 NetworkAgentInfo [WIFI () - 104] isDefaultNetwork=true
06-13 16:32:13.564 D/ConnectivityService(12159): Switching to new default network: NetworkAgentInfo{ ni{[type: MOBILE[LTE], state: CONNECTED/CONNECTED, reason: connected, extra: <manuallyremoved>, failover: false, available: true, roaming: false]} network{105} nethandle{454377263117} lp{{InterfaceName: rmnet_data0 LinkAddresses: [<manuallyremoved>/29,] Routes: [0.0.0.0/0 -> <manuallyremoved> rmnet_data0,<manuallyremoved>/29 -> 0.0.0.0 rmnet_data0,] DnsAddresses: [<manuallyremoved>,<manuallyremoved>,] UsePrivateDns: false PrivateDnsServerName: null Domains: null MTU: 1500 TcpBufferSizes: 2097152,4194304,8388608,262144,524288,1048576}} nc{[ Transports: CELLULAR Capabilities: MMS&SUPL&INTERNET&NOT_RESTRICTED&TRUSTED&NOT_VPN&VALIDATED&NOT_ROAMING&NOT_CONGESTED&NOT_SUSPENDED Unwanted: LinkUpBandwidth>=51200Kbps LinkDnBandwidth>=102400Kbps Specifier: <1>]} Score{50} everValidated{true} lastValidated{true} created{true} lingering{false} explicitlySelected{false} acceptUnvalidated{false} everCaptivePortalDetected{false} lastCaptivePortalDetected{false} clat{null} }
06-13 16:32:13.565 D/ConnectivityService(12159): Returning BLOCKED NetworkInfo to uid=10041
06-13 16:32:13.573 D/ConnectivityService(12159): Returning BLOCKED NetworkInfo to uid=10267
06-13 16:32:13.574 D/ConnectivityService(12159): Returning BLOCKED NetworkInfo to uid=10261
06-13 16:32:13.601 I/ActivityManager(12159): Start proc 5622:com.fsck.k9/u0a183 for broadcast com.fsck.k9/.service.BootReceiver
06-13 16:32:13.607 E/AndroidRuntime(12159): *** FATAL EXCEPTION IN SYSTEM PROCESS: ConnectivityServiceThread
06-13 16:32:13.607 E/AndroidRuntime(12159): java.lang.IllegalStateException: command '390 network permission network clear 105' failed with '400 390 setPermissionForNetworks() failed (No such file or directory)'
06-13 16:32:13.607 E/AndroidRuntime(12159):	at com.android.server.NetworkManagementService.setNetworkPermission(NetworkManagementService.java:2687)
06-13 16:32:13.607 E/AndroidRuntime(12159):	at com.android.server.ConnectivityService.updateCapabilities(ConnectivityService.java:4954)
06-13 16:32:13.607 E/AndroidRuntime(12159):	at com.android.server.ConnectivityService.rematchNetworkAndRequests(ConnectivityService.java:5389)
06-13 16:32:13.607 E/AndroidRuntime(12159):	at com.android.server.ConnectivityService.rematchAllNetworksAndRequests(ConnectivityService.java:5521)
06-13 16:32:13.607 E/AndroidRuntime(12159):	at com.android.server.ConnectivityService.disconnectAndDestroyNetwork(ConnectivityService.java:2538)
06-13 16:32:13.607 E/AndroidRuntime(12159):	at com.android.server.ConnectivityService.updateNetworkInfo(ConnectivityService.java:5652)
06-13 16:32:13.607 E/AndroidRuntime(12159):	at com.android.server.ConnectivityService.access$1500(ConnectivityService.java:198)
06-13 16:32:13.607 E/AndroidRuntime(12159):	at com.android.server.ConnectivityService$NetworkStateTrackerHandler.maybeHandleNetworkAgentMessage(ConnectivityService.java:2203)
06-13 16:32:13.607 E/AndroidRuntime(12159):	at com.android.server.ConnectivityService$NetworkStateTrackerHandler.handleMessage(ConnectivityService.java:2342)
06-13 16:32:13.607 E/AndroidRuntime(12159):	at android.os.Handler.dispatchMessage(Handler.java:106)
06-13 16:32:13.607 E/AndroidRuntime(12159):	at android.os.Looper.loop(Looper.java:193)
06-13 16:32:13.607 E/AndroidRuntime(12159):	at android.os.HandlerThread.run(HandlerThread.java:65)
06-13 16:32:13.607 E/AndroidRuntime(12159): Caused by: com.android.server.NativeDaemonConnector$NativeDaemonFailureException: command '390 network permission network clear 105' failed with '400 390 setPermissionForNetworks() failed (No such file or directory)'
06-13 16:32:13.607 E/AndroidRuntime(12159):	at com.android.server.NativeDaemonConnector.executeForList(NativeDaemonConnector.java:515)
06-13 16:32:13.607 E/AndroidRuntime(12159):	at com.android.server.NativeDaemonConnector.execute(NativeDaemonConnector.java:411)
06-13 16:32:13.607 E/AndroidRuntime(12159):	at com.android.server.NativeDaemonConnector.execute(NativeDaemonConnector.java:406)
06-13 16:32:13.607 E/AndroidRuntime(12159):	at com.android.server.NetworkManagementService.setNetworkPermission(NetworkManagementService.java:2684)
06-13 16:32:13.607 E/AndroidRuntime(12159):	... 11 more
06-13 16:32:13.616 W/DropBoxManagerService(12159): Dropping: system_server_crash (1956 > 0 bytes)
06-13 16:32:13.834 E/FrameworkListener(12080): read() failed (Connection reset by peer)
06-13 16:32:13.887 E/AndroidRuntime(5622): FATAL EXCEPTION: main
06-13 16:32:13.887 E/AndroidRuntime(5622): PID: 5622
06-13 16:32:13.887 E/AndroidRuntime(5622): DeadSystemException: The system died; earlier logs will point to the root cause
06-13 16:32:14.109 I/wificond(5653): wificond is starting up...
--------- beginning of main
06-13 16:32:15.042 W/audio_hw_utils(5654): audio_extn_utils_update_stream_input_app_type_cfg: App type could not be selected. Falling back to default
06-13 16:32:15.042 I/AudioFlinger(5649): AudioFlinger's thread 0xe83034c0 tid=5740 ready to run
06-13 16:32:15.043 D/audio_hw_primary(5654): adev_open_input_stream: enter: sample_rate(48000) channel_mask(0x17000c) devices(0x80000004) stream_handle(0xeb35a880) io_handle(22) source(1) format 1

The <manuallyremoved> entries have been manually replaced by me and were not like that in the original catlog.