EDIT:
Here is the raw block, try "submitblock "
Like in the debug window console? It responds with "Safe mode: Warning: Displayed transactions may not be correct! You may need to upgrade, or other nodes may need to upgrade. (code -2)", and the information tab still lists 312933.
EDIT: I don't know what I am looking for, but I see nothing in the log that would seem to correspond to the submitblock.