I recently had some 5" oak unfinished, glue-down, wood floors installed on a house that I am remodeling to flip. Let me start and say that I have used this hardwood sub on at least 20+ houses including new installs and refinishing and have never had an issue.

I just had my 7th coat put on this floor this morning and it still doesnt look right!

What you can see are several lap marks/applicator marks and lots of bubbles. The applicator marks are the main thing. He will make it right and come back free of charge but he isnt figuring out the problem.
He has blamed it on it drying too quick, drying too slow, the mineral spirits he was using so he changed that, then he blamed it on his applicator so he bought a new one, he has tried a couple of different finish sheens, and tried a different grit for the buffer.
Would it make a difference if he used oil or water based stain and/or poly then put the opposite poly on it? I know the rule for paint but not poly.
Any help would be greatly appreciated. I have seen a couple of puddles too but I think that was his error as well as a few places where it looks like the poly didnt take. I am getting frustrated with him. Thanks in advance for your time!