im currently testing resident drawer and gpu occlusion culling for my game.
While using GPU occlusion culling i noticed a really weird bug.
Sometimes textures start flickering like in the screenshots below.
When i turn of gpu occlusion culling everything is fine again.
Such triangular flickering artefacts are typically caused by numerical error in coordinate positions (See examples) and you can prove/disprove this by making the World position of the flickering region close to the camera while the camera is at (0,0,0).
Although HDRP camera relative rendering text indicates that such numerical error is handled, it is not possible for the rendering pipeline (HDPR or otherwise) to solve error created earlier in the application pipeline. Evidence of HDRP numerical jitter with Unity asset.
Another way in which this type of effect can occur, even close to the origin, is when surfaces are so close together that calculations based on even highly accurate coordinates cannot resolve what is in front or behind. The first resolution step should be origin-centering, as indicated above. Then, if the coordinates are not sufficiently accurate, separate the two surfaces by a little and test again.
So that probably rules out the most common cause.
I was actually looking at the triangles appearing on the green ground surface and the significant change of the edges between the green ground and the white terrain behind the tank.
The missing/displaced components in the top image appears to be a completely different issue.