I have a user I am running some Commerce order tests with. I have 6 orders they have placed. If I add a Commerce Customer Info field to their profile, I can see all their past orders on their Profile in the Users area (left side of screen below). However, if I view one of their orders in the Commerce Orders section, the Order History section only ever shows the current order (right side of screen below). Shouldn't it show all their orders like on their profile?
The Order History is the history of that particular order and not designed to pull in other prior orders from that customer.
You might want to make a feature request if you want to be able to see customer histories in the order view: https://github.com/craftcms/commerce/issues
....if they're a registered Craft user you can use the email at the top to get to their profile (and thus to that field) of course, but that doesn't not help for guest users.