Random incompatible glyphs in 3405

[GeorgSeifert]

Latest cutting edge 3.4 (3404) a little buggy

I get “these glyphs are not compatible” errors on some composite glyphs when exporting a variable font which worked without error in build 3402. Also, the “incompatible masters” marker does not go away even when I fix the compatibility of glyphs. Only after closing and reopening, the glyphs are not marked as incompatible anymore.