All I can tell you is that I have several Lyman moulds that have the cavities machined off-center, looking down into the cavity with the sprue plate open, the cavity in the left block(with sprue plate screw in it) is further forward than the right cavity, some as much as .005". The outside of the blocks will be perfectly flush when mated, but the cavity halves don't line up. All my moulds are off the same direction, I think Lyman's boring vise is worn out and the blocks get sheared away from each other from the torque of the cherry.
I fixed one of these recently by filing one side of the alignment holes out and peening the other side to shift the hole locations slightly and slide the right block forward (away from the handle hinge).
Haven't had much luck with Lyman fixing anything I sent back, but you might try it anyway.
Gear