Abscission and compartmentalization are distinct, visually different mechanisms plants use to manage damaged or unnecessary tissues, fundamentally differing in whether the tissue is removed or isolated in place. The margins being yellow/tips are a strong indicator K is having problems
Only thing you have regularly been adding is bio grow mixture too much NH4+ (cation). Im guessing your tap water is a little hard, when there is too many cations in a medium it can skew uptake (lockout) various other cations this is called antagonism.
If it was Potassium def alone she would present on old growth given K is mobile. Too much NH4+, Ca+, Mg and K, lockout can present against a nutrients mobility/all over.
Flush, reset, need to return medium to a balanced ratio. All that organic nitrogen will take 4-5times more water to separate from soil particles.