Colorspace error while editing Color font

While working on a color font with five colors in one palette, I’m occasionally getting the following error, which I don’t know how to interpret:

-numberOfComponents not valid for the NSColor Catalog color: System textColor; need to first convert colorspace.

And it says the file cannot be saved (which is alarming). I can temporarily “fix” the problem by choosing a standard color from a list, but of course none of those are what I want. All my colors are defined with HSB values.

I’m using version 2.6.6 (1350). I know–I ought to upgrade, but I’m terrified to do it.

Any guidance about what’s going wrong?

Not sure about the color error, but regarding Glyphs 2/3: you can download the Glyphs 3 trial version and run it side by side with Glyphs 2. Glyphs 3 can also open and save Glyphs 2 compatible files to ease the transition.