This happened to me as well, it fucked my whole plan up too! I had about ten plants(2 weeks in) and a couple seedlings outdoors doing GREAT, I started super early so they would vegg for a long time, and I come home one day and all that is left is 7 stems...no fucking leaves or anything, just a lil sprout stem sticking out...looked like the leaves were cut clean off, I still dont know wtf it was...prolly some lil lizard or critter though...well actually im positive it was a critter, not bugs, not humans, cuz no person would be dumb enuff to try and rip off seedling leaves lmao I just had to start over and keep it pushin....pissed me off though