There is another bug that I can produce when this component glyph is set to non-exporting, but is used in another glyph. Then the same error appears unless the smart setting is changed with the slider and then changed back to its default setting.
Thanks for the file. I fixed it.
But those brace layers are not exported so you most likely should not export those glyphs.
And I don’t know your full setup, but it might be that you are better off with corner components for the series instead of using a smart glyph as a stem stump.
Actually this glyph was not my design, but I used this as an example to isolate the problem that I was having elsewhere (said another way, this particular component was never meant to be exported, but it seemed strange to me that a component would not export by itself even if it exported fine when used in a glyph).
I think I understand how you deal with brace layers, but I only just understood today that they create rectangular divisions of design-space as I had always presumed a triangularization (so do correct me if I am wrong!).
I think what might have happened is that I found a font that was designed with an older version of Glyphs, but had problems with export in Glyphs 4 (and possibly even some problems with a recent Glyphs 3). Are you trying to be fully backwards compatible, and if so do you want to receive such examples? Be careful with your answer, because I think I have seen things that really should not have been working but did anyway (e.g. incompatible components that still export fine)
