Red and far red are the primary light colors that drive flowering. Blue light controls the plant shape (short and compact), red drives cell growth. There could be "too much of a good thing" going on but, without a reading of the spectrum that's hitting the plant, it's really a guess.
This
link will take you to a light that's sold in two versions; one for veg, one for flower and
this is an example of a "full spectrum" light.
Are you sure that you got foxtails? I see lots of nugs but nothing that looks like foxtails. Some strains naturally fox tail but, as I proved with one plant, too much light can cause foxtails, also.