I wouldn't worry,
leaves turn yellow once the plant is almost ready to harvest🌱.
It can also be nut burn. Reduce the nutes intake. Give the plant ph balanced water.
I think ur plant is almost there.
Happy harvest🌱!!!!
You have to act fast. same thing happened to me recently too. Try playing with PH. I grow in coco and tried to lower the pH to 6. And this started to happen to me. I increased the PH back to 6.5 and i managed to save 2 of the 3 plants. Good luck & let it grow!