Maybe. I think it depends on the players. Some will certainly try to come up with new tactics. Others will simple look at the first round and say "It deals X damage each round regardless, so we will kill it in Y rounds or we won't be able to so we need to flee."Isn’t it the opposite? This creature is unique enough that regular tactics won’t work, forcing players to come up with something different.
I've got players who can and will do that math instinctively within seconds of the results of the first round. And they will resolve the rest of the encounter in their heads less than a minute later. For my players, no randomness means the results of the encounter are known at the end of round 1. Might as well call it then. Not fun for us.