I usually include in my fonts the mathematical symbols ohm, micro, pi and increment as well as corresponding duplicates with their Greek names (and unicodes) omega, mu and delta. Now I noticed that glyphs adds Greek in the OS/2 table unicodeRange. Now Microsoft Word (2016) thinks that the font supports Greek and tries to create a Greek preview in the Font Menu on the right side of the menu. But because the rest of the Greek characters are missing, it only shows .notdef several times (in my case a question mark). When I customize the unicodeRange with a custom parameter, then the preview is correct. Doesn’t it make sense not to display Greek in the OS/2 table unicodeRange if it doesn’t contain all Greek characters?
Why add the greek glyphs. What you need are the math glyphs or all Greeks. But why just those few?
How the unicode ranges are calculate was discussed a lot. And I think Glyphs follows what was agreed on. So I think the problem is not that the bit is set but that you have those few greek glyphs.
Good question, I guess for legacy reasons. I remeber that in the past the greek math symbols had not the math names, for example Ohm was called Omega with unicode 2206.