painting job question

[space-time]

F/U: the bubbles that we left alone disappeared overnight. The bubbles that we tried to poke a needle into to let the air out now looks slightly worse, I think it's time to get the X-acto knife out and do surgery and paint again. Luckily those are up in a hidden are so a small touch-up job should be OK

[OWC Jamie]

I've seen those ( or something similar ) and like you've found, if left alone they go away.
Seems to me they are a reaction of the cellulose fibers in some of the paper lining the drywall. Absorbing water from the paint, reacting, losing the moisture and returning to a flat state.
I've only seen them where there is no mud, just paper, so it has to be something with the paper, or the paper's adherence to the gypsum, whatever . If it were the paint they'd appear everywhere.
An advantage to skimcoat ?