If it's a problem for Factorio it's also a problem for others, so definitely something to fix on the AMD side.
From time to time, it can retry the test, because software frequently changes what it spends time doing.
I wouldn't be too worried about this personally, as configuring the few really sensitive apps with ProcessLasso or Aniancy is pretty easy.
Factorio players don't necessarily know anything about computers. And you don't know if they bought this CPU or if it came with their fancy prebuilt.
A properties page for the executable with a checkbox for “favour stacked cache cores” or some such.