Microbubbles when cold smoothing ABS with acetone-- ideas on how to fix?

[Geiger]

Photo of issue, couldn't upload for some reason:
https://i.redd.it/kk4w6755ba361.jpg

Currently using Atomic Filament's black ABS.

This piece was sanded with 120 grit, then 800 grit. Surface painted with acetone then given a 10 minute vapor bath. Was allowed to rest overnight, then re-sanded, surface painted, and given another 10 minute bath.

I've had this issue with various lengths in the bath, with and without painting the acetone on first. Sanding the print seems to make the problem worse, but its not smooth enough without a preliminary sanding.

Sanding only makes the holes bigger/worse. I've had a hard time filling them due to their small size. Spray paint won't fill them, bondo putty is overkill. This has happened on dozens of pieces with various rolls, including freshly-opened ones.

Ideas on what's causing this how to fix it?