This article is in progress and will be continuously updated as new cases come in.
Your process is to create a temporary index, add records to it, then rename it to your new index. Your temporary index no longer exists at this point.
Point of failure: You try to add records to your temporary index after it was renaming it to your new index, then rename it to your new index again. When you try to add records to an index that doesn't exist anymore, it won't have the settings of your current index.