I've just noticed that my pet [pet not found] apparently has negative 22k in stored exp.
I've no idea when this happened, I adopted her from the centre originally and maybe she's always had it and I never noticed before. I don't battle with her so it's not a problem as such, but I feel it probably isn't right :P
This usually happens when a page lags and reloads so it buys the stats again. You can even it out by battling a bit with her. If you don't care either way it is fine to leave her.
Dexter by ❤
I filed a Ticket in Help and this is NOT the answer I got. They claimed to not know and asked me to keep track of my EXP next time.
That someone else is having this problem says it's not just me though.
Yours looks like a different issue. The OP's pet was adopted before Morostide started and they said they don't battle with the pet so it is more likely not the bug that you had during Morostide. In the past there was an issue with the page refreshing and double buying stats.
Dexter by ❤