Underline weight in variable fonts in Illustrator vs InDesign

I have a three-master file that interpolates underline weight as expected for OTF & TTF flat files

masters are Thin | Regular | Black. Regular is chosen as VF origin, with the custom param set as such.

in Illustrator, underline thickness will only ever render as the VF origin’s specified weight, but offset seems ok.

in InDesign, underline thickness renders with the underline weight for Regular in weights up to Regular, but with correct underline weight for weights Regular and heavier.

I have custom UnderlineThickness & UnderlinePosition params set on masters, but not instances.

wasn’t sure if I was doing something wrong here, or if it’s a known issue in Adobe apps. couldn’t find anything on their sites addressing it.

(edit: thought I should include these, just in case)

Glyphs doesn’t support variable stroke and underlines, yet.

you said “yet” so I take that to assume it’s on your radar. yes?