How about the pinholes in joint compound too? Will a second coat of paint fill these in? One does not!

I think the pinholes are tiny bubbles that burst as they dry, leaving tiny craters. Some paint has more of a tendency to foam up, but the impervo wasn't one of them as far as I recall. New formula? Better brushing technique?
Pinholes in mud never fill with paint. Use spackle after priming, then spot prime, let dry fully, and paint.
Casey

Thanks. Doesn't seem like it will.

I had some of those turn up in crevices also (Kilz oil primer). I cut them with a utility knife and probably sanded a bit before next coat to get rid of them. Will watch for air bubbles next round!