Oren was thinking very hard :
On Tue, 29 Dec 2015 14:40:30 -0800, "Eagle"
wrote:

Question: is there a preferrable primer to use? Or ones to avoid?

Thanks

Try scraping off the paint and use a stone or metal wall scraper to get
the old paint off, then use driwall topping compound and a trowel to
smooth the wall.

The question is about paint primers. Don't let facts interfere.

I don't believe in painting over primed plaster. After 30+ years as a
plasterer, I avoid priming plaster walls, both interior and exterior. A
bit of work and you avoid old paint lifting after priming.