Since a move between two containers involve two separate update calls from the frontend, normally, both containers get locked : However, during the first call, only the 'target' container gets locked, and during the second call, the 'source' container gets locked.
Since however the fix in
HSTTWO-3314, the second update can now fail because the source container already during the first call gets it 'last modified timestamp' updated. As a result, the frontend does the second call with a timestamp that is not in sync any more, and thus an error is returned. For example
As a result, the 'source' container never gets locked. The frontend also shows an error popup that the page gets reloaded. After this, all seems to be fine again. However, if the editor 'discards' his changes, the moved container item is gone from both the target and the source container