Took apart one of my Panasonic cordless phone handsets to clean the keypad and after re-assembling it, the charge indicator on the LCD display is stuck at one bar even though the battery is fully charged. Swapped batteries with one of the other handsets and it's fine but whichever battery is in my newly cleaned handset shows one bar. When I put the handset on the charger base, it beeps, the handset's charger light goes on and the display reads "charging." All seems normal but it never gets to full bars and the battery feels warmer than usual to the touch. The handset works fine, so far, in that I can dial and use all phone functions. What did I do wrong in the re-assembly?

Lands Phones - Panasonic