I don't see a problem on the wailer, but on the combination of it with that already hazardous environment.
I went through a portal to get keda out of it. A wailer pushed me in the corners right as I came through since the chunks were loaded. So what happened was that I fell out of the world as my screen was still loading and I wasn't able to do anything about this (you have to see the entrance to understand how this happened, but the corners must be filled since there is no block to prevent one touching the block that instakills you and make you fall out of the world, this block also destroys your stuff)