I have a 1981 Gottlieb Volcano. Lets assume as we all know, it was routed.
I sanded and touched up the playfield.
I clear coated it with 2pak.
It had to have a kazillion plays on it before I clearcoated it.
Was it dimpled before, not really noticeable but lets assume yes.
The wood should have been completely compressed by now.
It is now dimpling.
I suspect it is the thickness of the 2pak. The clear is about 15 months old now, curing would not be the issue.
It is not the lacquer of old and I think the NIB games are clear coated with modern coatings and are likely thicker than the once over lacquer of days past.
Unfortunately , dimpling is not new, it is not consistent from game to game and sadly we are so anal in the hobby that it comes up to be rehashed once a week.