My plant is starting to yellow at the internodes, ...

Hi @Moneystacks74! It looks like some Boron or Iron deficiency, but it's probably a lockout more than a deficiency. Your soil looks really wet to me (at least on your latest pictures), an overwatering scenario could explain why your plants are not able to manage nutrient intakes anymore: roots are flooded with water and old nutrients, you may have salt buildups in your medium, and the rootmass cannot breath anymore. If you're confident you did not overwater, then it's probably pH-related, a wrong pH range would have quite the same impact on your plants, and would result in a weird lockout / symptoms of deficiencies. Make sure your pH-pen is perfectly calibrated and give your soil a good flush with plain pH'd water, then let the medium dry (you can help it dry faster with a tiny fan blowing onto your container's surface). Now that you're into the flowering stage, be careful when it comes to watering, you don't want the medium to be wet for too long, or buds could be affected by mold/mildew. Hope this will help, keep us updated and happy growing! 👊