What is causing these screw pops?

[pulck]

I would drill elsewhere, finding a decent place for screws to fix and then fill in old and new holes.

From the photos, it kinda looks like you have plasterboard over a moisture resistant backing (maybe).

I would expect that there is a timber stud running along the wall. I have no idea why the screws are at an angle.

I suspect that the problems are the result of the screws being buried to too deep.

Try drilling above or below the screws holes and see if you can get a decent fitting.

Standard plasterboard is 9.5+mm the backing might 18(?)mm. If so, a 50mm plasterboard screw might suffice.

I previously tried driving in a 75mm drywall screen just beneath one of the existing screws. I drove it in straight/perpendicular, not at an angle, and it never bit. There's clearly just a void directly behind these screws.

Could it be that the stud somehow sits in the corner of the wall (remember - this is a dormer) and that is why the plasterer used very long screws and driven them at an angle?

If so, I'm not quite sure what to do. I could, of course, just fill the holes and hope the screw pops don't come back! But ideally I'd like to understand the issue clearly.

 

[Koolpc]

I agree. You need to find the studs. You could make several things holes looking for the stud. In the corner sounds right.

You have holes to fill anyway so what's a few more if it means finding where the stud is.

 

[robinbanks]

Perhaps the screws are driven at an angle because there is a hard stop at some depth shorter than the screw

For example you can drive a 120mm screw at 45 degrees into a 100mm piece of wood that’s screwed to a wall, but if you try drive it in at 90 degrees, it will stop after sinking 100mm

Perhaps too there is a gap behind the wall as well as this fudgery, so the board that has been plastered isn’t actually pinched against a solid backing and will pop forever more thanks to wall vibrations (slamming a door maybe?)

Cut a section out with a multitool and show us inside the wall. Oscillating multi tool hole cuts are easy to repair if you keep the square you cut out

 

[Wayners]

I think the screws have gone through plasterboard and are not doing anything.
The plasterboard is loose as not tight to wood so this pops the plaster.
Remove screws and move each one up as an inch.
Before you move them use a 10mm dill just to take top layer of plaster off. Go slow and easy, as that will help the strength of plasterboard surface when you tighten screws.
Go slow tightening screw so you don't also bust through.
Fill holes with toupret powder filler.

I doubt that will give anymore trouble.

Oh. Wood must go virtual looking at the pink mesh squares.
I think that was put up the corner to stop the mistake and popping screws but it did not work