How do I stop waterproof ceiling paint from peeling in the bathroom?
You ask how to stop it from peeling. Scrape it all off, properly prepare the surface, then repaint. Peeling paint is caused by poor adhesion to the underlying surface. Your's could be one or more of a multitude of issues: damp or wet surface; skimmed surface not cured prior to application; skimmed surface not primed prior to application; surface not sanded properly; chalky, dirty, dusty, greasy surface; glossy surface; etc.