Jerry Ellingson If I had to guess, I’d say it is an issue with the plate, is the 2nd grind using the same knife as the 1st grind, or do you have a knife for each plate?
mdseaside suggestion is a good one but the only thing that I can come up with is too much going down the throat at once. On the second grind, you want to add small amounts down, this will actually speed up the grind. Denny O I like the trickle term!
Another possible cause is a crack in your plate. Hit it on some solid metal, or hit it with something solid metal gently. It should have a clear ring to it. If it has a crack it is going to make it so the knife can’t seat snugly against the plate, this could cause that. HerbcoFood I think if the knife was in backwards it would have been done the same on the first grind, which sounds like it did it no problem.