Hello,
I had this sudden charging problem myself. My FP2 is 3 months old and is no longer capable of charging a battery. I know it is a problem with the USB port because I ordered a brand new battery from the online shop and it behaves exactly as the “old” one. Unfortunately, bottom module is still out of stock on the online store.
I’m in contact with the support desk to understand what to do… Meanwhile, I’ll get an external battery charger. With two batteries I should go along well 