I was going to mention the possibility of pollination, if you had any males around that's typically what happens when they get pollinated. However, if that's the case you should see those hairs curl and recede. Otherwise it could just be the strain, I had that concern (pollination) with a new strain last round, hairs went red right after the flowers popped. Turns out it's just the strain (Pure Power Plant or PPP), half the hairs were white, half were reddish-brown. Just watch it but unless you had some males around or are pulling air in from outside you should be fine.Sometimes but not always it can indicate that they are seeded if im not mistaken. I had a few in my grow early on but they are hardly noticeable now with all the white. I wouldnt worry too much, just keep an eye on them.