Pulley on Harmonic balancer not flush with fan pulley

Was the water pump pulley lined up before removal?
The one thing that occured to me that might jam up the damper from getting all the way on is the key in the crank snout getting loose a bit, and the damper hub kicks it up out of the keyway a bit when installing and the damper hub consequently jams on it. But I would think that would hang it up with much more than 1/8" from the proper seating position.