genetics. it simply takes longer to bloom because the ruderalis gene is not as strong in that particular plant.
nothing to worry about per se, just be patient and keep it healthy, if it is still not showing flowers by the time the ak finish then i gues it isn't an autoflower and you will have to switch your lights to 12/12.
snafuu,he has pulled the leaves off the ak plants and they have more buds than the GW so if anything this experiment proves pulling fan leaves makes your plants flower faster right? (only joking by the way)