I'm not trying to charge the battery immediately afterward, usually the next day, so I think its had time to cool down completely.
I only have two rapid chargers, I didn't keep any of the regular chargers I've had in the past. I've had an M18 XC8.0 do the 3 bars showing when completely charged thing and it was under warranty. The offending M12 XC6.0 I have now is no longer under warranty, so no help from Milwaukee there.
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What I've often wondered about is battery "rebound" or "regeneration" or whatever its called. It seems like you can use a tool pretty hard (something like a grinder or sawzall) and observe the battery charge level at say, 2/4 bars. Quit using it and after a while, it will show 3/4 bars after its cooled down a bit. I think I've noticed this more with HO batteries.
Perhaps when the hatchet "stalls" out on a cut, I should not try and get the last few cuts done before it won't turn on again. Hmm...