Negative quanta [unconfirmed]

[bumbletowne]

Normal PVP2 match, I blackholed the opponent, after which he was able to play all of his cards as though he still had quanta, which took him into negative quanta. Any subsequent clicks on my end just ended my turn, I was unable to play additional cards.
(http://imgur.com/vpwc2)

[Aves]

Ah, the desynchronization error. Rather misfortunate, but all too common.

Quote from the confirmed bugs list:

1.  Desynch
Symptoms:  Your opponent's deck, cards, health, and quanta keep changing rapidly.  Both players disagree about what happened.
Causes:  Various reasons.  If you lag too much, the computer will take over for you, causing problems on your opponent's end.  There is also a known bug with the PVP system.  By pulling a three man monty, and challenging each other in a triangle, all sorts of no good shenanigans happen.  Other known causes of desynch include voodoo doll shenanigans, playing flying weapon with no weapon in play, using cards that require very repetitious animation, and having a tie game. 

[furballdn]

Seems like a desynch error. The little ! mark on the top even says errors may happen.