Just want to add, this is a wallpaper glue issue. The bes thing to do now would be scrape the loose stuff us a product called Gardz, this is a problem solving primer that I use on all my wallpaper removal projects. Repair your walls as needed, you may need to skim coat the entire wall, sand and apply another coat of the Gardz. Now you are ready for paint.
If by some chance all the crackling paint comes off, mix amonia and warm water solution and wash the walls. This should remove any wallpaper glue that was left over!:thumbup: