Are you otherwise getting a good spin of the numbers and a little bit of a delay after it stops before the number is awarded?

If I recall correctly the numbers & lights are controlled by one of those little Gtb match type units, check the alignment of the wipers vs the contact boards and that the wiper contacts are pretty much centered on the board contacts. And possibly if the two boards were way out of correct position before being tightened down, they could end up with them out of sync by one position. One wiper would be the lights and the other for the relay circuit of each number.