Looks good. One is feeding differently than the other. The lighter one could be working thru the nutes faster than the darker one. Or you are actually feeding one more than the other idk your setup and details.
Some phenos are just lighter too especially if its a new strain. Just look for the dark one becoming overfed and the lighter one from being underfed. Looks like youre doing a good job.
Just a guess but the one is back in a corner and the other is by the step seemingly getting more hrs of direct sunlight. w/o knowing if it’s just camera angle or something that’d be by guess
Some phenos are just lighter too especially if it’s a new strain. Just look for the dark one becoming overfed and the lighter one from being underfed. Looks like youre doing a good job.