Purifier frozen during the transition to the last phase

It happened to me twice in a row already, with Maven, it just stays frozen without attacking or dropping life. If I stop attacking him, he starts regenerating ES. ES also drops if I attack him again, but not the HP.
Closing the game and entering the map again doesn't fix the issue.

My build is a BAMA with doomfletch (ele dmg).

3 times now, and this time from 1st to 2nd phase

After the patch, this bug is still there. 4th time in a row now.