My FP3 has serious problems

[OldRoutard]

And another example here:

Sudden battery drain out of nowhere

Hello, suddenly my FP3 has a very unusual battery drain. It went from about 100% down to 2% within 6h. Should have been at least 70% remaining. Yesterday everything was fine, today not. I tried tracing down the drain, not successful. There seems no unusual CPU usage. I even switched off the phone, opened it, removed battery and then reassembled it and switched it on again. Also I uninstalled a couple of apps I haven’t used since a while. It didn’t help. Now I even ru the phone in dark mod…