Hey Freaky. I saw this when you first posted, and I too have nothing, which is why I hadn't responded sooner.

My first inclination would be a dodgy batch of paint. Are you using rattle can nitro?

The fact that you've sanded and re-sprayed a few times with the same result, the most common denominator to me is the paint. Those spots almost look like solvent is somehow getting through unmixed.

I'd contact the paint supplier along with your photos and see what they reckon. Sorry I can't be of more assistance.

That's a nice quilt and colour. Hope you can get it sorted.