EDIT: Bug was the result of a typo in the source. It's been fixed now.
Minecraft Version: 1.18.2
Forge Version: 40.1.0
Steps to Reproduce:
1. Pen a snow golem into a small area with partial-width blocks (I used a 1x2 area surrounded with deepslate tile walls)
2. Push the snow golem into the walls
3. The walls will disappear. If they do not, start from scratch by removing the golem and the snow on the ground. Sometimes it takes a couple tries. The golem may also destroy the walls without being pushed.
Description of issue:
In the latest recommended version of Minecraft Forge for Minecraft 1.18.2, Snow Golems are capable of destroying blocks that they come into contact with. It appears that this only happens with partial-width blocks, like walls, fences, and the like.
To replicate this behavior, you just need to create a snow golem inside of a small 1x2 fenced area and push him around a little bit. It may take a couple tries (kill the golem, break the snow, respawn a new golem and push him around at the walls a bit), but eventually the walls will be destroyed (actually, removed, they will not drop) and replaced with the snow the golem leaves behind. Looks like it's happening because the golem is for some reason leaving trails on the blocks occupied by partial-width blocks, and the snow then deposits and overwrites whatever block is already there.
I've tried replicating this behavior in vanilla Minecraft, but it doesn't appear to have this issue, so it must be a Forge bug. This bug was reproduced with no modifications besides Forge itself installed. This occurs on earlier versions of Forge as well, at least as far back at 1.18.1.
Debug.log: https://pastebin.com/TRQdaFNg