Need more help yellow leaves

[Quarinteen]

Hello guys. I am finding out I suck at growing. I have been having issues with one of my plants. The leaves were getting yellow. It was suggested to transplant them from solo cups to bigger pots. I used 1 gallon. The leaves went back green and looked good for a couple of days. Now it’s back to yellow and worse than before. Any help would be appreciated. I have another plant exact same everything and it’s fine

3x4x6 grow tent.
1200 w led and 2 600w led
Humidifier which is kept around 60%
Soil base
Lights at 12 inches or so

If you need anymore info please ask. Thank you again guys.

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[Zee]

Had to go back to your original post, to confirm my thoughts.

Those leaves were touching your soil, and in a nutshell, your leaves soaked up so much nutes, it killed itself.

Looking fine, keep at it. Trust you will have plenty of leaves soon enough.