I'm late but I'm here.
I had a problem with aphids, I managed to solve using water and detergent only on the underside of the leaves and I removed the eggs by hand, this solved the yellowing problem a lot.
We are in the 4th week of flowering and I noticed that many of the lower leaves are yellowing and the yellowing is rising, I watered it with banana and beet tea. Is it lack of nutrients? Look at the pictures.
looks like your plant has Nitrogen deficiency. Even though it is flowering, it still needs some Nitrogen to sustain itself! feed it some nitrogen and you should be fine.