Pooling is when you get a heavy area, like a puddle. What you have is more like heavy stippling of maybe extreme fisheye. We have done 3 coats in a day but it generally is NOT recommended. My guess is that the coats were applied before the prior coats were sufficiently dry/cured. If it's a single component finish (no catalyst or crosslinker) it might be oxygen curing. Application of multiple coats deprives prior layers the oxygen they need to cure. I suspect that could be screened thoroughly with 100 grit, buffed with a maroon pad and coated again, once a day until it gets the proper film build.

And IMO there's rarely a batch of "bad finish". Finishes are made in huge batches. If your contractor got a few gallons that were bad, there would be hundreds or thousands of gallons out there. The exception to that would be if finish was stored improperly and allowed to freeze or get too hot. To be safe the contractor should probably get some fresh finish. If the other finish did have an issue some could be applied to a fresh piece of wood to check it.

It looks like he rolled with a contaminated roller. A full redo is at hand.

thanks for the comments, both! So, indeed orange peel/fisheye. He tried something yesterday, by buffing down and treating it with something. Then reapplied the top coat. It was much better, but the pattern is still there so he's going to have to sand right down. The issue is that the source of the problem cant' be identified. We went over the many different potential causes. He repaired 2 sections of flooring from damage and removal of marble in front of the fireplace, and the effect was present on the new wood as well. So that to me, logically, means it's not parafins, oil or silicone residue in the wood. Also, the orange peel is uniform over the entire 500+sqft of floor. Humidity, temperature, air flow etc are some others... I raised contamination (applicator, batch of finish, residual sawdust etc) but I suppose that I would agree that it would be extremely strange to have the effect cover the entire floor if it was contamination. He's not spraying. It's still possible but... likely its the application, or the product. It happened after the 3rd coat. Other floorers he consulted mentioned a couple of similar cases - after the 3rd coat. He was confident that there was enough time to cure between coats, but I'll insist that we leave larger gaps and wait. So maybe there's something off with the product or the conditions causing the product to behave like after 3 coats have been applied. Potentially.

All to say though, he's sanding down and starting anew. We're disappointed of course, it's been stressful because every time we return home it's a mess. It's delayed the reno, and of course the conditions in the house with dust and fumes isn't ideal over such a long time.

This seems like one of those things that is never sure as a cause...? Thanks again for your comments!

I think the culprit may be a combination of what I and G&S suggested. If he rolled the finish AND the under coats weren't cured enough I imagine you could get that surface appearance. I would think that buffing with 60, 80 and 100 grit would do the job but at this point the finisher probably wants to go with a sure thing. It's important to respect the drying times from the manufacturer when he gets to that point. He may have been trying to expedite the process and it came back to haunt him. Don't want to make the same mistake twice.

Thanks, yes, I spoke to him and he said that he will apply 2 coats on the first day. I told him lets look at the mfger's instructions first before we do that, and stick (no pun intended) to that. He'll use another product than the one he's been using for years (which is why he was also surprised). I'll update in case anyone is interested in the future. This type of thing is unfortunate, but because of the nature of the not 100% stable products out there (or at least, not as much as oil based) perhaps someone might benefit in case they come across it also.