Thanks for the input, but I don't think that's the issue.. and if it is, I don't like the part where I can't do anything about it

It mentions that the fungus attacks seedlings or early vegetative growth, while my plants have been on flowering for more than a week now. Then again, there weren't any pics to compare, so I don't know..

Any other ideas ?

I had a 26w CFL light (125 "real" watts) quite close to them when this happened, could that be the reason ?