AsNoriuanswered grow question 2 years ago My guess. First they have too much N, could do trick.
Second you underwater them, all photos look like this. This could lead to proper salts build up ( hard to disolve ).
Third they look either hungry, either having root issue, both look very not possible tho ...
Forth wrong ph , sometimes even meter lies, are pots really light, or just top soil dries out ? That will give you answer.
Either lockout from wrong ph or N toxicity.
If they were heavy feeders and got used to, could ge hunger, but i give that 1%.
Run off ppm and ph would tell a lot in such case, just take samples right.