Graph view - 1 note missing from group

So I grouped all my notes to colour them yellow, but just one file was left grey. Its a sortspec file, from the Custom Sort plugin. I have more of these files but just this one, from my root folder, was left. Am I missing anything?

It’s hard to say without knowing what’s in the file and what your group setting is.

Also, I added " - 1 note missing from group" to the post title so people browsing the forum will have more of an idea what you’re asking.