There have been bracket layers before (while using G2) but I managed to interpolate without them (and deleted them) in G3 (latest version). Problem is that the rendering does not change (see lower part of the pic, left range is variable). Also the exported file shows problems.
What happens if you close and re-open the file?
Do you have a “Replace/rename glyphs” parameter in those instances?
‘Rename’-parameter – that was it! Thanks!