A user on dewiki reports a DBQueryError after move. He moved 3 times with an error and than it works. Sounds like a timeout.
[WPmtzArAEFEAAB9ovAMAAABX] 2017-04-21 06:59:41: Fataler Ausnahmefehler des Typs „DBQueryError“
T150453 fixed something in that area.
Please have look in the logs. Maybe it possible to avoid timeout in that situation. Thanks