I'm not sure why the author didn't attempt to dive deeper into the error message he saw. amd_vcn_dec sounds like it's an issue with the GPU's video decoding logic. If there's a timeout when trying to process a decode request, it may be that power management for the GPU is buggy somehow. Given that this is a server build and idle power consumption is likely not a big deal, I'd suggest pinning the GPU power state to see if it resolves the issue (see amdgpu.ppfeaturemask and amdgpu.runpm kernel parameters).