Every App crashes, if you connect a BT input-device
I'm seeing the same behavior between my Samsung Galaxy A tablet and a Zagg Flex Bluetooth keyboard. When it connects or disconnects, the current app reinitializes itself or force-closes. In order of misbehavior, I see apps do one of three things (with one example each): force-close (Lightning Launcher), reinitialize and lose any work-in-progress (ES File Explorer), or gracefully handle the connection event as if nothing happened (Chrome). Performing a search on Google, it seems that this is "by design:" Android will reinitialize an app when the BT keyboard connection status changes, but apps can declare to Android that the app will handle the event itself and therefore avoid the reload.