After updating to the current Marathon community (1.6.352) version, noticed that URI's defined are no longer displayed in the UI friendly view.
Previously (v1.4.9), URI's defined via fetch syntax or via the legacy URI syntax had records in both the "uris" element AND the "fetch" element. So UI display showed them properly (I'm assuming it's only paying attention to the "uris" element.) However, don't go back to this as it was non-optimal, since it resulted in an invalid app json that could not be directly resubmitted to a marathon instance...
Now with 1.6.352, only the "fetch" syntax is available in the resulting Marathon definition, but the UI doesn't display what those values are. (It's not a major issue though, since the fetch definitions are in the app and are being used properly.)
Screenshots attached of the relevant portions of the UI display, the UI available JSON, and the app definition available on the /v2/apps/ endpoint.