After riding in a boat in the water for a while, I would hop out at land edge and the boat would disappear. It wouldn't be in my inventory and I couldn't click where it should be to destroy or get in. Exiting and reentering the world made the boat reappear in the water; it would disappear again after riding in it.

It didn't happen every time but enough times for me to report. I was on a realm when this happened so I'm not sure if this is realm specific.