When Lighthouse complains about an aria- attribute it provides incredibly vague feedback, e.g.:
"[aria-*] attributes do not have valid values"

Surely the failed test knows which attribute and which value are the issue. (This, incidentally, is occurring on an element literally built from the W3C's reference implementation; I may have typed something incorrectly, but this isn't helpful.)

I'd be willing to help if I could get some pointers on how to do so.

What is the motivation or use case for changing this?
Usability tools (and a11y is, at bottom, usability) should be usable.

How is this beneficial to Lighthouse?
Improve adoption and use.