A few years ago we had a water line break on the 2nd story and had to repaint a large part of our 1st floor ceilings. Now repainted the ceiling areas and they are peeling all the way to the drywall paper. Unpainted areas are fine. Did contractor potentially paint before ceiling was dry? Other cause?
Applying the paint before completely dry is one possible cause. Another is the original paint and drywall was damaged by the water, drywall can become powdery when exposed to excessive water. This would cause the existing paint to loose adhesion.
It could a combination of these two possible causes.