Autos do their own thing and can look different. I have two Northern Lights autos in week 6 today, both started the same time. There does not appear to be any stunting or deficiencies during the grow.
#1 sprouted 2 days before #2 and has lagged behind #1 the entire grow. Last week #1 took off and #2 continues to move at her own pace. I am pleased with how #2 is turning out, bushy true to her Indica heritage. #1 growth pattern looks like it is conforming to it's Ruderaris background, but same leaves/color as her sister. I have a side by side in photos for week 5 of my grow diary you may want to check out.
Not much you can do about it, I would let them do their thing and see where it goes. The first 3 weeks are painfully slow.