I've made some changes to my routine since I last posted in this thread -- clarifying, balancing protein and moisture better -- and my hair is much healthier and more manageable now in general.

I've noticed my grays that used to do this are far less noticeable now that my hair is overall in better condition. So I think there is something to be said for these hairs needing more moisture, protein or both. Or there might be build-up preventing the moisture and protein from doing their work.