I wanted to try and kill my horse, since I got the same issue as in the post. I died and both me and my friends "UI" or "game" freaked out.
But in the meantime we got stuck on ship controls with no way to release them. After a relog it was possible to release the ship, but then nothing else was possible again and the ship controls where visible in right corner even though I was walking on land...
Patchy Mcpatchy.. where are you.