This is the kind of bug that open-source people love to work on. But, are people experiencing it in the wild? If so, Microsoft will fix it. If not, enjoy the other things Microsoft spent their time on otherwise and forget about it.
If queries.FilterHasError().Count > 0 Then
I had developed the add-in using 32-bit Excel. This was an extremely confounding troubleshooting experience. Eventually Google & Stackoverflow rescued me from believing I was going crazy.