How to reproduce:
# Import the attached package (Reproducible with both URP&HDRP, I exported repro from URP project)
# Open 108.a_ShaderGraphIntegration_URP Scene
# In the Scene View pan camera around
# Notice that Sorting Test Effect start flickering

Notes: It is reproducible in Game View and Scene View when tweaking position of the camera, resizing window, panning camera around in the scene view, reproduction can be tricky and not reproducible from the first try. I've attached visuals showcasing the issue

It looks like that animated objects has to be added to the scene (in this case VFX-Space(tangent) otherwise it stops flickering (this is the case in Play Mode too)

Reproduced with 2023.1.0a11