Ahh okay I bet that was it. Temps were too high.Genetics and stress, like mentioned above are the biggest causes. High light levels and high temps can cause a plant that doesn't normally fox tail to do so. Sometimes it's just the strain and it's a pain to trim with some of them.
Oh yes I remember trimming my foxtail plant too, was so leafy. And if I remember correctly the potency was shit.I had it happen really badly last year when I tried an experiment with UV light and I scorched the crap out of my plants. Two strains that don't normally foxtail looked like bumpy knobs with the tops being the worse. I'm a good bit more conservative with my light levels now and keep temps in the low 80s. I like easy to trim strains and those sucked.
Just keep in mind if the foxtailing is genetic then that weed can absolutely be fire. Including the foxtail. In this case it's just another shape of bud. Ain't pretty but smokes the same.Oh yes I remember trimming my foxtail plant too, was so leafy. And if I remember correctly the potency was shit.