It is currently possible to override of the uuid key in configuration entities. However this is problematic because the configuration importer needs to detect configuration renames, recreates and deletes using the uuid key and this is hardcoded because the module that supplies the configuration entity type might not yet be installed.
Ensure that the uuidKey is uuid.
Write patch with tests
User interface changes
Restrict uuidKey to only being uuid.
Data model changes
Why is this an rc target?
If a configuration entity used an uuid key other than uuid it would break ConfigImporter.