@HugoJ hey hugo, which fontbakery profiles did you ran? I had a similar setup with 2 master at both weights extreme. But not getting any complaint in regard of “Regular” not being the VF origin.
fyi, I ran the TypeNetwork, and Universal profiles on fontbakery web.
Is that currently the correct approach? As I remember, Adobe adds the origin before all instances (unless it’s the same as the first instance), so you get 2 Regulars