IMO - a couple potential reasons dude. First - this is def. genetic and the plants look sweet👍. Very nicely done. That said, you’re coming into the final weeks so it’s not surprising that she’s starting to show off some colours. If ur on the flush yet, then the added colour is nutes in the leaves being consumed by the plant as well. The other thing of interest that has me wondering is how accurate is your temp. Variance indoors? A 4 degree diff. Day vs. Night isn’t much but temps do factor in significantly with this kinda colour change. I now do this purposefully in my space and can vary the temps from 26 to 17 throughout the cycle day/night. Even more if a vary the extraction fan speed. If you have the option then you can get some awesome results👍. Either way, nothing to be concerned about at all. These colours would have me giddy bro!👌