In flower i regularly do a four week into flower cleanout to remove dead leaf matter. Soil is better for keeping leaves green than coco or sunshine, but there is always some yellowing. Ive found using veg nutes until about four or five feeks after flip helps keep them a little greener longer. The yellowing i can see here looks mostly like normal plant consuming nutrients in fan leaves, causing fan leaves to yellow from the tips back and then eventually causing leaf death when shes taken what she wants from it.
This should have started about a week ago for normal plants and it will keep going until you chop em.
A cool thing to notice about this is that the plant usually eats the leaves that are either in a low light spot, or blocking buds from recieving light. Plants are smart.