Instances has become partially disabled

I had a file set up with 6 masters (3 weights, 2 widths). I had a set of instances defined that showed and exported correctly. I added 3 more masters (an additional width), and the instances were all broken. Now, when I remove masters, back to only 6, instances are still broken. All my stem weight numbers are defined. Only a 4-master file will allow me to define and generate instances. I updated Glyphs yesterday; did something happen to Instances in this version?

NOTE: I am fully aware that it is not recommended to use more than 4 masters. But technically, is there a reason this can’t work?

Could you send me the file with all masters (maybe with only one glyph)? (support at this domain)

If you are not interpolating something between the widths (or are you?), then perhaps it is better to split the two widths in two separate files.

What do you mean by, ‘instances are broken’?

Five masters can work fine, that is if you stick to one of the constellations described here (the b&w graphic about half-way down):