How strange is this?

Hi mate, I think the colour is due to cold temps. When temps are too cold for the plant she slows right down but also more of the purple colour shows through due to these temps. I had a similar issue with my Banana Krumble. My temps were not ideal and she was very dark in comparison to other grows i saw of the same stain. It is part of the pheno but sometime won't come through until she is well into flowering. I hope this helps, good luck and happy growing