Yellowing leaves

Newbie here first grow, 2 GG#4 autos 1 purple lemonade. Fabric pots for w/perlite 600w led AN bloom and big bud.
Only having trouble with the purple it looks like there's some yellow leaves but it I turn off led and check with regular light with no purple leds on it looks ok with no yellowing. Not quite sure what to do.

also they were all planted at same time and one GG is ready for harvest but the other 2 look like they got at least another month to go, is that normal or could that be because I topped those other two plants?!

How old are the GG's

How often are you feeding? At what ec are you feeding, medium your using ? No one can help if you only put what's wrong with my plants and post up a picture,
Ppl need all relevant info of your grow , hope this helps

They are both at beginning of week 11 from seed, will post New pics of each plant

Feeding about every 4 days or so, whenever pot feels dry. Last feed was at 850 PPM, using AN bloom and big bud. Growing in FFOF with 20-25% perlite
Also using vander life 600w led

This is one GG ready for harvest

This is second GG looks like at least another month and same age as last one

His is the purple lemonade I am having trouble with week 10 from seed