Hi. I have encounter the same issue. I have a battery (16-10-24) in Transit, after ordering the wrong battery a few weeks ago.
As this is for a friend / Client (not me), the client was reporting some issue with opening his laptop. I checked it out, and I opened the laptop (it's a bit difficult) even thou I had cleaned the hinges and that area at the back of the laptop. I ALSO noticed that the battery (I purchased a new power supply off eBay) that suddenly the battery is at 100% and the laptop is working without external power..
What would be going on here? Please?
I also weeks ago did that SMC reset thing