Phosphorous deficiency?

New to growing but I have been through a few grow cycles and I have to agree. Seems like a normal color change in flower. I'm not sure what strain you're growing but some turn purple when close to the end of its life. Especially if grown in cooler temperatures. I think this because the overall leaf and its structure appears to be healthy. Not drooping, no wilting ect ect. Possibly a little nutrient burn as some of the tips are toasted. Could be old or new but this purple appears normal to me and I wouldn't sweat it.

Yeah I dunno about you guys but this looks more like late flower fade and some color coming thru..

This is light stress on a plant in late flower. If you look underneath the leaf you will see purple on the underside. That is the tall tell sign , Damage is done already all you can do is raise your lights and/or dim them

It looks like a molybdenum deficiency. Usually caused by too low of PH.

I see your pistol are nice and vibrant so it shouldn't be overfed. Best to give a good ph watering until you have some runoff water you can read. Make sure your ph is in range and see where your ec is at. Not sure what you grow in so I can't say what your values should be. But they also look like they need a little grow nutes in the mixture as well as your bloom nutes. I'm betting your total ec is low in your substrate.

To me - considering I don't know ligh it looks more like final fade away . Girl goes her life and now she is almost at the end You green leaves are pale a bit, but I would bet that it's lightly underfed but healthy plant.