Hey Growmie,
I just had this happen with a Bruce Banner Auto, it grew so tall, and the buds were super unformed as it was growing, the stems were long and weak and it eventually broke. Turns out it was just the pheno, I'm growing the same strain now and it grew the correct way. So to sum it up, it happens sometimes, doesn't matter if it's an autoflower or a photoperiod even though it does seem like the photoperiod genetics are a bit more stable at times. Feel free to shoot me a holler if you ever need any help, I'd be honored to assist you. Hopefully, this was helpful, and remember ... "Happy Growing" and "Free your mind one puff at a time".