Description:
Previously, when you were to run createIndex(es) on an index that already exists, but with a different name, you would get the 'IndexAlreadyExists' message. Now when you try to do that, it will return 'IndexOptionsConflict' because the index from the createIndex(es) command you run with a different name does not exist with your name, but with a different one.
Engineering Ticket Description:
The createIndexes command fails to report an error when an index is not created with the specified name because an index already exists with the same keys but with a different name.