Hey. Very interesting grow here! So you have the same gentetics and upbringing but one plant is doing very well and the other is somewhat struggling 🤔 assumption is the feed is the same? I can only think it is having issues with the roots. Possibly as you have planted them quite close in the same pot . Which I do like the idea... looks like roots have been damaged/under stress. My first Go to would be some stress relieving feed. Have a look at something like biobizz algamic or the bio heaven. I know this company and feed, but there are certainly others out there that will help. If you can . Without too much messing about try and move it a few inches further away. Take some soil from the outer edges, (Go quite deep)gently push the girl in that Direction and use the same soil the fill the gap where the girl just left. You would have to be v carefull doing this. I would definitely recommend some root/stress feed though. Best of luck