Our Data API checks scopes, collections, and indexes for each JVM type and creates them if necessary. Then awaits for all indexes to be online before proceeding. It seems that concurrent index creations may initialize indexes with the same name in Couchbase 7.0 Beta.
Exception there were actually 3 indexes with the same name and one of them was alternating between ready and error state.
Not all of our indexes end it this way but seems like that the retry mechanism behind index creation or concurrency would do such a thing.