I have never put any Pva on the wall before dry walling, damping the wall has allways been adequate.
If you put the finish on just as the browning is beginning to set there should no problem with any suction.
Let's point out what the problem is with it for most of us, it's the fact cement-based products mix with plaster which causes the two to de-bond (a tiny chemical reaction causes the two to sort of cause atom-sized explosions, causing the two particles to not bond). So providing we're not talking about cement on plaster, plaster on cement, I think there's no problem in using PVA.
Sirapite (a gypsum finish)was used on cement backings for a large number of years with no problems
i've erased my post. Doug said the same. i thought something wasn't right there with what I said.
I'll just shut up then lol