Q.I Have A Strange Oddly Colored Single Branch On My Tricolor Beech. Wondering Why That Is.
I have one odd branch of a tri-color beech that is probably 20 years old. It is deep solid purple. Where the rest is the typical light and dark combination. I’m wondering what this indicates? Or if it’s anything to be concerned about. Everything else seems healthy.

Certified GKH Gardening Expert
It could just be a sport or a mutation. Also make sure it isn't coming from below the graft. If it is, cut it out. You can cut it out anyway if it bothers you.
https://www.gardeningknowhow.com/garden-how-to/info/plant-sport-mutations.htm