Hey, after looking at your light and set up and past grows. I'm more than sure I know what's wrong with your othetwise very healthy and happy grow. It's actually the complete opposite. It's slight light deficiency. Move that light 30cm away from seeding to harvest and at this stage it should be turned up to 100%. Also wouldn't hurt to use a micro if your not? Otherwise your plants are very healthy if it were light stress you'd have droopy leafs and by the time light stress would do that you'd see droopy leafs first. Happy growing, good luck.