MDE is experiencing some issues with being able to customize MagicBands for on-site stays. I just tried to select MBs for my trip and not all colors were showing as choices. When I went into customize for other family members, different color choices were showing, but still not all of them. It took me 5 or 6 tries to get the right colors selected for the right people.
I online chatted with a CM and suggested that this may be related to some programming changes to accommodate the recent announcement of the availability of discounted upgraded MBs. She did some digging and said that the problem is exactly that.