humm.... pull on the sugarleaves, if they easy to pull out you are having some budrot going on
first sign are the sugarleavfes, disccoloring, getting brown
i hope it is anything elase
Normally i would say its a overnuking with nutes , but i have to look closer
older pictures are in purple light, haard to see anything, but i wouldd go with an imbalance in your grow.
mainly in nutrients.
but pull on the sugarleaves, if they gget loose very easy it is budrot,