Vince

yeah i think that's you few month back that told me that Nirvana introduced some new CBD strains after discontinuing the previous ones : )

Yeah but pulled lot of dead and yellow leaves with some of them, they look more healthy on the photo than they really are (for the 4 right ones in the tent)

that's not obvious from the photo, but i pulled many yellow leaves rather high in the plants on the 4 right ones. And bottom right one is lacking magnesium.

For one or two of the  4 lighter green, not sure about the other two

i think it could be magnesium also , but i don't have some cal mag actually

as said a tad bit clueless i already had this issue in the past, and adding some more N didn't really seemed to help but can't say for sure.

here's a good articles on the topic of various causes for yellow leaves:

The causes and solutions for yellow cannabis leaves. - RQS Blog