sounds to me like the 1st time they painted it, they ended up with solvent pop, where it essentially goes off too fast, leaving the pin holes all over (my removed panels all did this when painted)

it is usually down to the mix, sometimes if its mixed with too much hardener, or if speedy hardener/thinners are used and then not mixed correctly

on the flip side to this, the 2nd time when the paint didnt dry, that sounds like the exact opposite, where the paint was mixed maybe with too little hardener, or standard was used when mixed as speedy, so instead of going off mega quick and solvent popping, it just doesnt go off

1st time round they could try arguing the toss with the paint suppliers and saying they gave them the wrong stuff, because in my case this did happen, but to then go to the complete opposite, just sounds like an idiot mixing the paint. you do mention during wet flatting the paint they managed to flat through the new and the old paint, that sounds fairly bloody amateur, so id say the sort of person who does that is the sort of person who wouldnt be the best at reading a mixing cup lol

and to then say they want to paint in solid 2k paint, says to me they just want to throw a load on, and then plan on flatting out the imperfections they know they will get, as they could then get any old retard to throw the paint on, then just flat it to death with no danger of flatting through a clearcoat