Hi, again, Chris. Sorry that I can't help. I have never run into this. But I think that you might end up having to have it stripped off and refinished. I think that the problem is in the poly so your contractor might not be the "bad guy" but he is still responsible for it. I would suggest that he call the manufacturer of the poly and ask them.
I don't think that varethane is the answer since it is just another brand of poly. The poly that I have used for floors does take a full 24 hours to dry before you can apply another coat--mainly so it gets hard enough to scuff sand it.