After taking my wolf with me in a boat, it will no longer fight mobs that I attack or ones that attack me, it just follows me around without reacting to combat at all. Logging out and back in does not resolve the issue, nor does restarting the client, but restarting the MC server process does fix it (until the next boat ride). I've been able to repro this behavior consistently. I still need to check if it happens after every boat ride or only when hopping chunks/continents - long trips definitely trigger it, I will take a short trip and comment when I find out if it's consistent.