When a module build is cancelled while it's in the init state and it is then resumed at a later time, the init handler runs again and fails because format_mmd is run again, causing the exception "Custom component repositories aren't allowed".
format_mmd
We need to either make the init handler idempotent, or not allow module builds to be resumed after failing in the init state.
https://pagure.io/fm-orchestrator/pull-request/1145
This issue has been migrated to Fedora Forge: https://forge.fedoraproject.org/koji/mbs/issues/1130
Please continue any further discussion there.