The denoiser sometimes gives some weird outputs for some render passes.
Try making a wireframe extra tex and turn on denoiser, for example.
It is also not great for volumetrics. It adds a bit too much of the background over the light rays.
I would be really cool if there were more controls for the denoiser, particularly for volumetric fog.
Which denoiser are you using?
The VRay Denoiser AOV
And checking the box for denoise in the attributes for each aov.
The VRayExtraTex with VRayEdges issue is reproducible - it happens only with the V-Ray denoiser engine (and if the VRayEdges is not part of the RGB). Logged it (VMAYA-13777) for dev investigation. As a workaround, I suggest using either the NVIDIA or Intel denoisers.
Mind if you send a simple scene for the volumetric issue?