This problem goes back years as demonstrated by this 456 Berea Street post from September, 2011. The key passage imho is:
In my opinion this is a case where screen readers take “screen reading” a bit too literally. Or, as may well be the case, browsers applying CSS too liberally before exposing item states and properties to screen readers through their accessibility APIs. I think in most cases screen reader users would benefit if list-style:none was ignored, or at the very least configurable to be ignored. Whatever the reason, as a developer it surely doesn’t hurt to be aware that list items often are not announced as such by screen readers.
Couldn't have said it better myself!
So… any chance you could patch Manifest to make the ordered and unordered lists more vanilla and less likely to trip up screen readers?