If there is a consensus conflict on the lock of a particular transaction, then the network goes into "defense" mode regarding that transaction and has to wait for a full confirmation before it can be spent. This is the right thing to do, and ensures that double spends are not possible (assuming the rest of the algorithms and code are correct).
It's worse than that:
If I control a majority of nodes*, I can confirm a transaction lock to the recipient of a double spend, then dump the transaction lock from all my nodes and double spend the coins back to myself with a new transaction lock which I hold until N blocks have been built.
"defence" mode cannot work as designed because of the nature of sybil attack.
*) there is a constant probability of success which increases with the number of nodes I own