Question about growth rate

I'm in the middle of my first grow, I actually have 4 different strains but my concern are the two autos I planted. The seeds are Nirvana Blue Mystic Autoflower. The plants were veged under a 48" 8 bulb T5 in my veg closet with my other plants under an 18/6 light cycle.

I put my seeds in a two part soil/one part coco mix in 3 gaillon containers on June 4, the plant on the left sprouted on June 8 and the plant on the right sprouted June 9, the growth rate (height wise) has always been a bit faster but nothing outrageous. On June 29 the plant on the left went into flower, thinking the other plant was a day or two behind it I moved them both into my flower tent under a 600 watt HPS bulb. The plant on the left began showing a ton of bud sites right off the bat and stretched out some, it took the plant on the right 5 days to start flowering and it hasn't stretched nearly as much as the other plant. Besides the growth and flowering time the plants look very similar (leaf size, bud sites, size of fan leaves), is it normal one day delay in sprouting cause such a difference in flowering time? Or can I just sum it up to less than stable genetics?

I should note that these pics were taken June 29, July 7 and, tonight; I also got a bit more aggressive with LST between the 2nd and 3rd pic, there were a lot of bud sites not getting enough light due to the tremendous growth. The plants are also 36" and 28" tall from the top of the soil to top of the colas, I thought most autos don't get that tall.

I grew one out and it was a nice plant. Started inside and put it out side to finish the last 2 months. Very nice bud I still have a .25 saved away.
similar to your second one.

Better pic in my grow journal https://www.rollitup.org/blogs/533514-diet-coke.html

they both took a different stance one is very indica/rudy and one sativa it is normal
one could be more demanding on nutes also this is the stage where (P) ,(K) and cal/mag play a important role not saying its not needed until now but if its a nute whore and burned the soil up and is living on just what you feed it it may be asking for more of something you just havent noticed

or like i said at first it may just be the indica , sativa flower time difference