yellow and crinkling leaves in canna coco any ideas

[tealeaves]

hi all

ive got 4 plants in coco,,3 ghs train wreck and an f2 haze i got from a friend on here

they are all female and 2 weeks into flower,,last week i started noticing some yellowing and in the last week or so the haze is getting some crinkley leaves..pics below

canna coco
canna coco a and b food
bio nova cal
silica

feeding ec 1.2-1.4
ph 5.7

day temps 24-26

night time 18

rh 35

has anyone seen anything like this before (haze crinkling)

i had been feeding 1.2 ec food but today i went with 1.6 could the yellowing off be because of the lower ec and the plant stretching because of the light change could possibly be taking more nutes inleading to the yellowing

thanks in advance