In areas where there are grass path blocks of a large size (we've only experienced the bug with grass path at least 2x2, but we're not sure if it works with only 1 grass path block) pets (wolves and horses for sure - livestock like cows, pigs, sheep seem unaffected) will sometimes appear to fall into the block itself, which usually only leaves the top of their head visible. All of our grass path blocks are surrounded by fence, so that might also be a factor.

What I expected to happen was...:
I expected my horse to stand still when I dismounted, and I expected my wolf to follow me on the grass path.

What actually happened was...:
The horse fell into the block, leaving only his ears visible, and he was unable to be mounted while stuck, and the wolf fell through the block, only leaving a small part of him visible. It should be noted that the wolf still follows and will become 'un-stuck' if you go several blocks away, but the horse remains unusable until the bug just eventually 'fixes itself' where the horse comes back up through the ground. Waiting for a horse to come back seems to take several minutes in real time.

Steps to Reproduce:
1. Place grass path blocks down in an area with fencing right beside the blocks
2. Befriend a wolf or tame a horse
3. Lead that pet onto the grass path and walk around for a bit
4. Sometimes they fall into the grass path block