Basically I have had some issues trying to paint a spoiler for a friend, im not new to painting ive done a few cars, paint repairs etc but im just not sure whats going on with this spoiler.

It came in a ready to paint primer, so I used 320 da pad discs and went over it by hand, then I panel wiped it and went over with a euro 1k grey primer, let that go off then I guide coated it and wet rubbed it with 800 wet + dry, after this I used ici base coat colour mixed with multi purpose thinners, let that dull off then used a euro 1k lacquer over the top. But as soon it started to go off it sank in places and also when I put it outside to dry off in the warm it started to micro blister in places which has never happened to me before,

This is the worst corner,


Then this is what I found when I removed all my paint and sanded it down further through the primer it came in, its like loads of holes?