I'm pretty sure that you are in the earlier stages of foxtailing, which usually happens on the largest colas. I use it as one indicator that my plants are finished flowering, as I usually don't see it until week 12 in Sativas. I use it as well as the Trichome color change to tell me when the plant is finished. If left alone, you will start to get long, skinny bud growth out of the bud's end. After a few of them merge together, it looks bushy, like a fox's tail, sort of.
While I use it to determine finishing of flowering, some strains are just prone to it and can foxtail before they are finished flowering. Some treatments can also cause sporadic issues with foxtailing, like
Triacontanol. I don't think it affects things too much, but the buds don't grow much or very well after you start seeing this happen. This is my opinion based on my past experience with some old strains and not the newer strains and hybrids that are prevalent today. It's hard to say what has been bred into some of these genetic lines anymore!