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.

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.