I tried to create an ambiguity duplicate of https://musicbrainz.org/release/e76dd3ca-4feb-46c9-9417-760654eeeb35. For both I used the "create based on existing release" function. Track editor looked fine, but already summary did not list those mediums that had not been changed. Upon creating the edit I eventually had a release with two instead of 13 mediums. Did that twice.

Source release https://musicbrainz.org/release/e76dd3ca-4feb-46c9-9417-760654eeeb35
Follow up release #1 https://musicbrainz.org/release/9fe1cb76-49fd-4936-85d7-79922e52b488
Follow up release #2 https://musicbrainz.org/release/37809734-8e38-4dc8-9b7c-ff175fa38ac8

Additionally, for the first release there were no edits associated / listed.