Disable masters results in -32767 for wght axis if opsz dropped

Hello, following scenario:

I have a file with two axes. First axis: opsz. Second axis: wght. If I disable half the masters (=drop the opsz axis), I get a fontbakery error telling me that the Reg instance axis location is not at 400, but at -32767.

If I switch the axes to 1. wght and 2. opsz in the Glyphs file, the export works correctly.

Do you have a test file at hand?

Sent. Thanks a lot.