This is caused by unique controls in different environments sharing the same name. "Control A" in Environment 1 will be assigned its own UUID behind-the-scenes, and another control also named "Control A" in Environment 2 will get assigned a separate UUID behind-the-scenes. When an import occurs, it sees that the UUIDs are different but the names are the same and prevents the import from overriding a potentially different control.
If "Control A" was imported into Environment 2 first, then the UUID would transfer and import/exports between the two environments can occur as expected. The full details are in this article: How to Import Controls with the same name in Assure – Infogix.
The best way would be to leave the production control as-is, delete the control in the lower environment, export from production to a lower environment so that the UUIDs match, make the necessary changes in the lower environment and then export/import the changes back into production.