m0useanswered grow question 9 months ago Autoflowers are more susceptible to shock, this includes transplant shock and overfeeding, over/under watering, heat or light stress as well. When it happens they go into early flower.
This includes things like HST, don't break any branches or take clones from an auto. LST is ok in moderate amounts.
It is best to grow autoflowers in the final pot from seed to harvest, no transplants and to feed them less then the advertised amounts. It could also be that the living soil was a bit to hot "over fertilized" for the autos and this may have contributed to the early flower.
I don't know the root cause of this, something in the autoflowers genetic make up.
I use this link a lot to work out my autos feeding regeme. maybe it will be of help to you as well.
https://www.autoflower.net/forums/threads/med-man-method-feeding-chart-ppm-ec.47856/
Good Luck!