While I was traveling in south america recently, my FP2 stopped charging normally. I would recognise the charger only when the battery is very low (blinking red led) but as soon as I would get the charging screen, it would stop charging effectiveely although the phone was telling me that it was indeed charging. When launching the OS, the charging icon would often say that it is charging, bu the battery menu in the parameters would say “not charging” at the same time.
I found out also that my phone would charge in fastboot mode.
I now have tried an other bottom module and it works perfectly with that new one, but I am just leaving this message here in case it helps others one day. Strange that the bottom module became defective in this fashion…