Those leaves are ussually dying first ,cotyledon
Don't pul them off, let them die naturally. It's like our belly spot, theirs connection to mum/ seed shel.
I would stop feeding them for two weeks, they are so small that feed in soil would be enough for all grow, you will bump into nitrogen toxicity any second ...
Maintain good pH, dry wet watering regime and you should have lovely nugs !
Next time try to feed later and less.
Have a look at recent Lex Blazers video :
m.youtube.com/watch
Less is more in weed grows ! Golden rule !
All the Best !