Cat in boat drowning

Just informing you, I named my cats 'Creeper Cat' for a creeper farm, so don't think its too weird, lol.  Anyway, the issue is I was trying to transport tamed cats about 2000 blocks from a village to my base in a hardcore survival world.  I had a baby cat in a boat and he made it just fine.  But randomly I tried back to back with two adult cats and they both somehow "drowned" while they were fully in the boat.  I was in F5 and tried catching it but the cat just randomly died and could not screenshot it.  I did screenshot the message and where I was when it happened though.  Sorry if there is a different similar issue, I just could not find a thread for it anywhere. Thanks!