The battle was hard but i managed to get the upper hand, but at some point of the battle, while my oozemancer was using his acid beam and ooze beam one after another, a few errors popped up :



what i could see of the enemy effects at that time in case it's one of them in combination to my beams leading into the problem :

It happened only for 3 turns of that battle when using my beams, then for some reason it didn't happened anymore (despite i was still using the same attacks) and fortunately didn't screwedup the game as i could defeat that boss and resume exploration without further problem.
no log as i had closed and relaunced tome4 to clear memory unfortunately before thinking of looking at the log.