Weird growth

It's just genetic variation. Your dwarf is leaning a lot harder toward an indica structure. Lots of breeders sell F1 hybrids(1st generation) because growers like the vigor they display but it doesn't make for the most stable gene pool in terms of uniformity. It's not unheard of to pull 4-5 different phenotypes from a strain if you pop enough seeds at a time. If you're growing inside and need to keep them close to the same height, LTS the top of the tall one down to even them both out. I'd recommend that anyway to break the apex dominance.