I'm trying to add a mixed index with one key to an existing graph.  After building the index, I do a commit on the JanusGraphManagement, and then awaitGraphIndexStatus(graph, mykey).call().  The resulting report says the index is REGISTERED, but if I look inside the report success=false and my key is in the "notConverged" collection, marked "INSTALLED".  Subsequent attempts to enable the index are not successful.  The key also shows up as INSTALLED if I look at what is returned from getGraphIndexes.  What does it mean for a key to be "notConverged", and what might I be doing wrong?  I've tried to follow the procedure in the documentation fairly carefully.