Spots on low leaf

[ballzmagee1006]

 

[Oldbay]

That may be just the start of the fade. Yellow leaves from the bottom up are a sign of nitrogen deficiency so you could add a little of yo want but the rest of the plant looks great and a good fade is great at the end

 

[Calyx]

Agree with Oldbay, as your girls are finishing they will begin to "fade" on the lower plant more and more closer to finnish.
Now if this is happening in week 3 of flower or earlier you are Nitro deficient.
Don't forget to blend your veg appropriately with your bloom gradually into flower to prevent early nitro deficiencies.