iCloud fixes
Apparently on iCloud there is no way to know whether a store is “the first one” that’s created in order to start seeding data but still avoiding duplicates. The current device could be offline and be using the fallback store while the same app on a different device could be running and already seeding its copy of the store, thinking that it’s the fist one. Hence the only way is to seed it and cleanup duplicates afterwards – something that needs to be handled higher up in the application layer – the one that understands the underlying data and able to de-duplicate effectively.