[MC-13704] Placing a boat in smp crashes the server

I placed a boat in some water, and now the server is not joinable.

Environment

Placing a boat in some water.

Actually, it doesn't crash the server. Rather, the player trying to ride the boat gets kicked off and is unable to rejoin the server.

Restarting the server does not help.

Confirmed on SMP for all players that try it. Unable to recreate in single player.

Confirmed on SMP, also. Same with horses. Player.dat file needs to be edited and "riding" tags deleted before player can connect again.

Yes I am experiencing this as well on SMP.