Apple Battery Charger - does not charge to 100%?
It’s hard to tell with this new product, that is really a normal battery charger. Rechargeable batteries should charge all the way to 100% especially when they are new. If you’re not getting a full charge, try depleting them all and fully charge them, see if that works. Otherwise, batteries may be defective or it could be a mouse/software misinterpretation.