i am a PPG certified painter for more than 25 years. i really haven't had ANY problems with PPG paints.
if OMNI clear coat falls off in sheets why hasn't it on my car painted over 6 years ago.
you must have slammed the base coat on WAY to fast or waited to long before clear coating.

the problems with the base coats being to thin is because the older colors were not reformulated for base coat just converted over to base coat. when this happens they take the single stage formula and add the clear tint them add base coat binders. when they do that it has 2X as much clear tint in the formula than if it were single stage color.