I'd say it's an issue with having a large area to photo, and once the lights are in, or close to the picture, it pulls the contrast out due to trying to compensate for the lightings sheer brightness. Might be a good idea to capture sections from above.when there is a sheer amount of plants to fit in one picture.
Photos come out great for me with the quantum boards on (3000k/5000k/660nm) as I have a small area, and can take a photo with the lights on without copping any of the glare from them in frame which messes with contrast. As soon as I take a step back and the glare effects the contrast, the image looks washed out.
TLDR. It's hard get a good image contrast when there's bright light sources like bright LEDs in frame. Like taking a photo with a window behind in a darker room.