Healthy Growth or Overlay? How to tell the difference?

Hello,
I'm growing some Hillbillies and Jack Frost and some of my tubs look like this. I've provided FAE at around 50% coverage so I don't think its overlay but just worth double checking since I can't seem to find any good information on the differences and I've not had tubs look like this before.

Any input would be greatly appreciated. Thank you!

6qt unmodified monotubs.

https://preview.redd.it/y86cs0tj8ujd1.jpg?width=2268&format=pjpg&auto=webp&s=70cfe522979f4f73ab434a63618a8986cb01b161

https://preview.redd.it/x0ufbzsj8ujd1.jpg?width=2268&format=pjpg&auto=webp&s=12f16ca60439100729cc629ec571a041d17cd6d1