Hey there, there is this issue with the Sniffer where they can get pushed into vehicles. Mine carts, boats, etc. With a boat, there can even be two Sniffers at the same time.

STEPS TO REPRODUCE

Go find or spawn in a Sniffer

Place down a vehicle which mobs can get into

 Watch the Sniffer fit in even though it's too big for the vehicle

Current results: The Sniffer can fit in the vehicle

Expected results: the Sniffer won't be able to fit (like in Java Edition)