I fully agree with your observations and assessment.
This is why in a previous post I tried to clarify that I did change my position on the nature of the bug(s) which we talk about in this thread. I used to think that they all are a result of AMD Vega driver problems … but I was wrong, because at least this case …
does show a different characteristic, as it clearly applies to other GPUs too.
PS: I also in the meantime migrated away from Vega to a new RDNA3 GPU.