Did you drip some fertilizer on it when it was younger? it's missing a leaf and the other had damage - either burned off or odd genetics. Most plants will grow out of early fugliness, if that is the case. Even with a few oddities, plants usually grow just fine.
if that's not a tri-leaf mutation and you have multiple growth nodes stacked on top of each other, then it's probably getting too much light. Looks like 2 nodes are super tight on the stem (1-finger and 3-finger leaves with a 1-finger missing). This would indicate too much light. if it's been too long, it may even get stunted before it starts to grow normally again.
i can't see for certain in the pics, but below assumes it's too tight....
doesn't matter if the other plant got the same light (just in case you say that in your head, lol). It matters how each plant behaves not our perception of treating them equally, which again, doesn't matter 1 bit if growth behaviour is off. React to the plant, not our perceptions or beliefs.
I think you can just move this to the corner where there is weaker light and wait for a little internode to develop (aka stem between 2 growth nodes). Don't let it stretch too much. You very likely need to shift it back to stronger light once it recovers and matures a bit. Again, internode length is a guide to light intensity -- too short = less light; too lanky = more light.
i know it costs more, but if time and scheduling is important, plant 200% the number of seeds you plant to use. This is much easier when they are free vs 20/pop. I use my homebrew seeds and freebies as 'filler' for the extra seeds planted. This way if you do have to replace one, you aren't losing 1-3 weeks or of growth. Keeps all th eplants on the same schedule and avoids negatives of genetic problems, that are more common than most realized, and human error.
Anyway, it'll never be as consistent as a room full of clones, but you can avoid all the less than optimal-to-bad outcomes that are visible from an early stage - slow growth and more than a few genetic defects.