obx RO water being used.
Alright, that leaves HEAT MOISTURE STRESS.
A few remedies to try:
Put your hand half way between the tops of the plants and the Lights. Can you stand the heat from the lights?
Is there a very strong FAN blowing directly on them, or very close to them?
What is the humidity? Need HIGH, like 40% to 60% in VEG, lower like 30% to 40% in Flowering. (Plants like high humdiity all the time but in Flowering, and indoors in a tight space, you risk bud mold with high humidity in flowering..........a cool temp and low humidity will help increase trichomes in Flowering)