Annie's Tibbers.
So, I'm not too sure if anyone else has seen this, but at least on OCE, Annie's Tibbers is experiencing a bug. While it's only visual, the HP number text above its HP bar isn't centred. The text is on the left, making the HP bar seem a loooot larger than normal. I'd take a screenshot, but it won't allow me in game. You can try spawning tibbers yourself in a custom for proof.