m0useanswered grow question 3 days ago here is a leaf chart for symptoms of excess and deficiency in cannabis.
https://420life.com/wp-content/uploads/2021/10/Marijuana-Leaf-Deficiency-Chart-scaled.jpg
To me it looks like its from cooler temps. but if that not happening then need to look at your feeds. Are you giving them enough, are you getting a good amount of runoff when you feed and is your PH on point. Ph looks ok to me. but without a EC or PPM value for your feeds its hard to tell.
You diary states your useing a SF-G3000 for a cycle of 20/4 and this is a bit overkill IMO.
The official site is suggesting a 50-60% dim at a 12" hang height for 18/6 in Veg.
https://www.spider-farmer.com/products/spider-farmer-g300w-cost-effective-full-spectrum-led-grow-light/