Yeah, Edge/* is going to detect separately from Chrome. The issue is, prior non-Chromium based versions of Edge would also have a user agent that looks like Chrome as well, so those older versions will need to be treated differently. :(
It's the same reason why everything still has Mozilla/5.0.
To be completely clear, I am suggesting this is a bug. It even looks like a bug, since it ironically tells you to upgrade to "...Edge" while saying Edge is unsupported.
This bug is specifically detecting the new version of Edge (which uses "Edg/") and allows users with other strings "E/", "Ed/", and even Spartan based "Edge/".
Someone intentionally added code to single out Chromium based Edge.
It's the same reason why everything still has Mozilla/5.0.
To be completely clear, I am suggesting this is a bug. It even looks like a bug, since it ironically tells you to upgrade to "...Edge" while saying Edge is unsupported.