I ran into export errors. Double checked the mentioned glyphs and found the problem in most but not all of them I found anchor points at the exact same position, moving them slightly solved the problem. Another issue was overlapping handles, that was also easy to fix. But the remaining glyphs do not have obvious flaws.
There is no hint in the glyphs itself (like the red circle when two anchors are at the exact same position or the visibly screwed up outline when handles overlapped).
How would I show the layers participating in the interpolation and what are layers participating in the interpolation? I’m sorry, I just got a glyphs license a few weeks ago and this is my first project.
This looks like a case where the path stroke cannot be expanded into compatible outlines. If you can send us this file (or a copy of the file with just the glyphs that cause issues), then we can try to improve the stroke expansion to stay compatible in these cases as well.
