Embedded binary is not signed with the same certificate as the parent app yet they are identical

Question

An app extension is causing a code signing issue. This app is already on the Appstore (with this extension) yet overnight for some reason when I have come back to this ap

Answer 1

For me it was not having the App Groups set up correctly on all my App IDs on the Developer Portal. Therefor the App Groups in the app didn't work correctly, causing this problem.