a simular thing happend to my plant just half of one leav started to turn yellow so i stopd the nutes just fed pure water for 2 days then i went back to nutes but i reduce the amont,in about 3 days the leav turnd back to normal
in your case ur not feeding nutes ur ph is prob higher than 6.5
and your plants are way too small to flower they wont hold the budd