m0useanswered grow question 2y ago I don't think this looks like plant pigmentation to me. I could be wrong though.
I normally find the purple strains go purple from the centre out and do it consistently and evenly this one is splatted and not even all sites.
Check you medium, make sure its not compacted or water logged. also make note of your PH as this kinda reminds me of something like a PH swing and compacted roots.
Good Luck!