Setting custom culling planes doesnt seem to work

Ive embedded HDRP into my project and im modifying the HDRenderPipeline code directly. The following code should, in theory, cull everything on the scene (or most of it at least, all the planes are intersecting at the same point with normals pointing towards the center) for a specific probe. The code is executed properly, ive checked, but in reality it doesnt do anything, everything is still being rendered. Am i missing something about culling in SRP/HDRP? I even tried setting frustumPlaneEquations in HDCamera, it doesnt seem to do anything either.

(Unity 2019.1.14, HDRP 5.16.1)

Code (CSharp):

1. if (TryCalculateFrameParameters(
2.         customPlanarReflectionCamera,
3.         out _,
4.         out var hdCamera,
5.         out var cullingParameters
6.     ))
7. {
8.     Plane[] planes = new Plane[6];
9.     planes[0] = new Plane(visibleProbe.transform.right, visibleProbe.transform.position);
10.     planes[1] = new Plane(-visibleProbe.transform.right, visibleProbe.transform.position);
11.  
12.     planes[2] = new Plane(visibleProbe.transform.up, visibleProbe.transform.position);
13.     planes[3] = new Plane(-visibleProbe.transform.up, visibleProbe.transform.position);
14.  
15.     planes[4] = new Plane(visibleProbe.transform.forward, visibleProbe.transform.position);
16.     planes[5] = new Plane(-visibleProbe.transform.forward, visibleProbe.transform.position);
17.  
18.     for (int n = 0; n<6; n++)
19.     {
20.         cullingParameters.SetCullingPlane(n, planes[n]);
21.         hdCamera.frustumPlaneEquations[n] = new Vector4(
22.             planes[n].normal.x,
23.             planes[n].normal.y,
24.             planes[n].normal.z,
25.             planes[n].distance
26.         );
27.     }
28.  
29.     if (TryCull(
30.         customPlanarReflectionCamera, hdCamera, renderContext, cullingParameters,
31.         ref _cullingResults
32.     ))
33.     {
34.         skipRequest = false;
35.     }
36. }
37.