“The instance is not defined correctly.”

I am getting this message when I try to export my fonts:

Some instances do not have the “n” image next to them. When I simply click on the instances (without editing anything), the “n” appears and I can export without the message appearing. Re-saving the .glyphs file does not seem to change it at all.

Small bug in Glyphs?

Can you send me one of the files?

Somehow, I cannot reproduce it any more. Maybe it has been fixed.

Had a similar bug today after adding a TTF Zones Custom Parameter just to one master and then clicking on an instance – then the n disappeared

This is a mor specific error that is easy to solve. The original only had to do the calculation of the factors for the instance.