It’s a dangerous world when it comes to old wallpaper!
I’m okay if it’s well adhered; it can work like “Glidwall,” hiding the cracks in the plaster. Once it starts to peel back, though, it’s often hard to know when to stop taking it off. Many of the rooms have a few layers, so they’re fine, and I leave it alone. The second floor hall and third floor were a different story.
The two rooms on the third floor were painted blue. The back room had poorly adhered paper, which I easily removed. The front room was tough to remove, so I left it, except around the cracks where it was easier to remove.

The blue area is where the wallpaper was scraped away before it was painted blue. The rest is where I removed the wallpaper. I prepped both rooms to be Glidwalled.

The lighter colored areas are where I scraped back the loose paper, then primed it with oil based paint so the ‘mud’ wouldn’t reactivate the paper glue and loosen it. That would be a bubbly disaster!
I really need to talk to you about this! We are having this EXACT problem in our house. Except all of our wall paper has been painted over and is now peeling off.