dying leaves...help!!

so my superskunk plant has been losing leaves consistently since a month before flowering, its now 5 weeks into flowering and the fan leaves are dropping off at an increasing rate!
About 20 leaves dropping of per day. its a large plant in soil, stem is about an inch diameter and the branches are pulled down to make a flat canopy ,completely filling its 1x1 m tent,its got hundreds of leaves left but if somethings wrong with it i want to fix it.
i feed it gp maxibloom ,epson salt ,trace elements ,its in a 5 gallon bucket , heres some pics ,
other than the leaves falling of the plant seems very healthy, and none of the leaves near the buds are falling of or yellowing the leaves in the first pic were just pulled off, i thought maybe the plant has reached its max size and is replacing old leaves but not sure

post some close up of those leaves on the plant. are they cupping? from which region of the plant are they falling off? you have a very large plant in a 5 gal. people are gonna argue with me, but i'll say this from my experience, if those leaves are coming from the lower sets and you are experiencing cupping, but are following closely to a recommended feed schedule and you're not overwatering, you are most likely seeing the early stages of root bound. need more info to make a determination and more time most likely. root bound doesn't strongly present for weeks. superskunk matures after 9 weeks and your flowers are looking pretty small for week 6, but what kind of light are you running? the leaves could be dying due to low light. these are some loose ideas. need more info, broski.