Coastal humidity and the blistering wall
The fix is diagnosis before decoration. A competent painter arriving at a blistered wall should ask where the moisture is coming from before quoting, and on a bad case use a moisture meter rather than guesswork. If the source is a leak, that is a plumber's job first and a painter's second. If it is ambient coastal humidity in a bathroom or kitchen, the answer is surface prep down to sound material, an alkali-resistant or damp-tolerant primer, and a paint specified for wet areas — not another coat of standard matt over the bubbles.
Sea-facing apartments deserve one more note: choose sheens deliberately. Full matt marks easily in humid rooms; a washable matt or eggshell in bathrooms, kitchens and hallways costs slightly more per litre and survives UAE condensation far better.