In at least some cases, the parallel resource menu isn't respective advanced prioritisation. To create a reproducible test case, the screenshot below shows the top of my prioritisation list (i.e. nothing is prioritised higher than the items shown). You'll see that various individual commentaries are prioritised, but that prioritisation is restricted to the book of Ruth.
Bringing up the Parallel Resource Menu from a Judges milestone, you'd therefore expect all the resources prioritised for Ruth to be ignored, and the first resource to be shown to be the TOTC volume. However, that's not what happens:

The bug appears to be triggered by any resources with the standard Bible datatype. Resources that use the BHS datatype don't trigger the problem. You can see that from the WBC volume, which is correctly ignored.
The bug also appears to be restricted to the parallel resource menu. Guides and look ups seem to work just fine.
This bug was first reported here. Judging from this post, the bug has been around at least since 2012!