TT Hinting preview wrong pixel size?

When I add a Delta for TT Hinting, the wrong pixel size is affected. For example, when I add a Delta for the font size of 9px, it affects the 8px size. See screenshot attached.

How come your pixel preview is so crisp, by the way?

The fuzzy preview is a Big Sur issue:

I have seen that post too. I guess I was assuming Ludwig was also on Big Sur.

Still not working in the latest beta (3087).