How much foliation did you leave on the plant? What were the temps reaching at night/day?
I know there is a direct correlation between how much of a temp difference there is at night that affects bud structure … also things like warm nights can elongate nodes and affect tightness. Also those auto strains are crossed with ruderalis and in my personal experience with autos grown by many others is that the buds just don’t compare to the normal seed. But again that’s my experience. If I were you next run I’d try a femized seed or regular . Also try some lst to allow for more light to hit the bud sites… it’s seams as if they didn’t get enough light. Maybe there wasn’t enough wind in your unit for that particular strain…
In my unit I allow an oscillating fan to run for 30-40 minutes twice a day. Cannabis is a wind pollinated plant there fire reacts to the wind by producing more buds because it knows pollen is supposed to come in the wind … try fanning your next grow a little bit if you use the same strain.
So many factors but it orobky comes down to genetics. Probly just got a pheno that grows in such ways