I have a phone running Android 9 that I have been using for a while for messaging, i.e., Line, Viber.
The phone has an iPhone style sim-tray, and for security reasons, I usually unplug the SIM when the phone is not in use. Very recently, I noticed the phone started behaving unusually whenever I plug in the SIM card.
What happens is that, a few seconds, maybe three or four after plugging in the SIM card, the screen suddenly goes black. The phone becomes unresponsive to any input for about four or five seconds, then the brightness gets turned up to the highest level and the Lock Screen is shown and the phone then becomes unresponsive again for a few minutes. This happens twice.
After this happens and I unlock the screen, I get a modal message telling me that "Find Device" has suddenly stopped.
Is this known behavior from a phone that's been infected with some kind of malware?
Where can I look to start diagnosing the problems?