I has some shitty results from Classic Arcade overlays also. Leveled all inserts, sanded perfectly flat, waited weeks before applying the overlay. The registration was horrible to put it nicely. All black key lines bubbled up. Nowhere else, only the key lines. I did not clear over it because there was no way I was locking that crap in there. I am not sure how clearing over the overlay would solve any issues because your clear is only as good as what it is adhering to. Junk...

Its a shame to because the colors are absolutely beautiful. Even with some missing shading. Very vibrant colors and sharp lines, at least on the over lay I got. Everything else about it is crap though. I think he almost has something its just not quite refined and it appears as though he has no intentions of refining it any further. There seems to be too much inconsistency. There is the Xenon here, the guy who started this post and literally everything in between.

I agree. He gave me two slingshot plastics which look fine to me. I guess he was anticipating me being unhappy with the overlay

It was cleared with a water based varathane. A chemical reaction that only effected the key lines? unlikely. It seems more to me that the issue would be in the way it was printed maybe, I am not really sure. It just seems odd that it would only be the key lines and not just random bubbling across the playfield.