Your coco coir looks a bit dry. That might be pulling the moisture off the skin. It's quite common to see this type of tortoise with peeling skin on the neck. It's nothing to worry about. I'd be willing to bet it will stop peeling if you kept the substrate with a bit more moisture - not wet, just moist.
I also reckon it's just shedding skin naturally. Nothing to worry about, in my opinion.
Tidgy used to do it when she was younger, but not as much now she's bigger and kept more humid.
Welcome to the forum to you and your tortoise.