I had a really weird one once, a buddy sent me seeds of an accidental cross Magnum auto x Dragon Flames, from the Dragon line once upon a time. Brother, friend, whatever made this cross and he told me he/they were getting 30% auto (I had expressed interest in autos at the time-I bet there's a post or a dozen from years past about them here somewhere and possibly this): first grow 90% auto, AND accidently crossed them with a GDP (GDP popped in in a tomato start and both got planted in the garden along with a dozen or so of the Magnum auto cross seedlings. God I'm stoned right now

So anyway I'm growing the F1 Magnum auto x Dragon Flames x Granddaddy Purple and I get like 2 or 3 that start to flower but stop. That's it, a month latter I'm pulling them out. WTF? Never seen since. Also, it was winter, about this time of year in my greenhouse without any additional lighting. Strangest fking thing I've seen. Just stopped flowering and maturing. Poor things were totally geneticly confused on what it should be doing