Code in mark & mkmk feature

Glyphs
1

For an algorithm that creates horizontal fractions, I need to use the mark and mkmk features. If I write my own code, the compiler complains that my lookups are duplicated,
while, in fact, they are not. If I select auto-generated code, the compiler complains of duplicate definitions for “mark_DFLT” and “mkmk_DFLT_bottom”. Any idea how to get out of this maze? Using Glyphs 3.1 under macOS 12.5.1. I don’t remember having such problems with similar code under Glyphs 2.
Thanks.

2

What lookup names did you used in your own code?

3

NumBar and DenomBar
However, I’ve tried other names such as pos_2, result in the same complaint by the compiler.
This seems to be a very basic error in the compiler.

4

Can you send me the .glyphs file?