As you can see on the pictures they got some light...

Hi @Madreefah! This looks like thrips marks to me. Take a close look onto & below the leaves while the light is on, those bastards like to enjoy the sun and suck the nutrients out of our plants. They hate wind, neem-oil, cold temps, pesticides, and ladybugs. Hope this will help, keep us up-to-date and happy growing 👊

These marking resemble PH fluctuations and a possible Phosphorus deficiency. The reality is that most of a plants nutrient problems like P/K deficiency is cause by the inability of the roots to intake the nutrients. Adding more/less nutrients will not solve the issues unless the PH is accurate and stable first. Because you switched to Bloom nutrients 2 weeks ago I am leaning away from straight P deficiency and leaning towards PH fluctuations causing a P deficiency. Here is a VERY handy guide to help self diagnose your plant https://www.growweedeasy.com/cannabis-symptoms-pictures

Yeah man madreefah, good job catching that early on ! What it is is the start of P/K deficiency because your plants are going well into the flower and the flower stretch. What you want to do is switch to bloom nutes, and add a booster and/or P/K asap and hopefully the leaves and yield won t be too affected since you caught it early. Congrats on some great plants , hope this helps you cross the finish line, dassit 🚀