so I don't honestly know if this is a bug or not, but it seems a little irritating if it is not. I set a basic rat to mine a select set of a few ores, it gathered about 8 blocks then ran up out of the mine and less than five minutes later the rat drowned. I couldn't find anything about this, and I don't know if it is intentional, but it seems like it breaks the functionality of mining rats. minecraft version 1.16.3

Fixed in 5e55839