Get rid of default weight axes?

I have a simple family: Regular and Italic (of that regular). In my masters I have the weight axes set and there is no custom parameter (axes) in the Font tab. How can I get rid of it? I can’t export the font, it say that ‘A’ is not compatible! :face_with_head_bandage:

Upright and italic designs should be in two separate Glyphs files.