When baby horses/donkeys run into a block they get stuck in the block and take damage. I tested it a few times by pushing them into the blocks and they take damage, some can get out by themselves other die. Fullgrown horses/donkeys don't have this issue,
63rd Duplicate of MC-13632, please use the search function to see if your bug has already been submitted. Currently over 58% of tickets are being closed as duplicate.