[Gameplay] Udyr's E- Bear stance doing true damage

I just had a game against a udyr, and during one of the fight I was killed by him and I looked at the death recap, it said bear stance did true damage. He had no red buff nor elder drag buff, it was just bear stance and it did true damage, which it shouldn't. I wasn't playing zac either I was playing gragas.

Please fix this bug, really disrupting to get killed by a full tank udyr as a tank just because his E randomly doing true damage which it shouldn't.