I had a team of "professionals" repaint the drywalls of a newly-purchased house.
A few days after they completed the work, two kinds of defects appeared on the walls, in a large number of different spots.
The first kind (depicted below) is the paint looking either depressed or protruded over fairly large areas (15-20 cm).
The second kind (depicted below) is the paint protruding and looking (and feeling) smooth as silk in the affected area.
The people who did the work claim there is an unspecified "problem" with the dry wall itself, but cannot recommend any specific course of action to rectify it. Of course they maintain they carried out the work with great care and competence. I don't trust them more than I would a 30£ note, but I myself saw them sanding and priming the wall before applying the new paint.
How can I fix this? I have some experience painting dry walls but I am no expert. Is this a case where extra preparation is needed, possibly involving repair of the dry wall itself?