Answer: You can use the search instancecount(2 to 100000) to return documents with 2 or more instances. The higher number can be anything, but a huge number such as 100,000 should be sufficient. You can also download the Ingest Report from the top menu Ingest. On the report, navigate to column "instance id". If the instance id has a ".2" or higher, this means the document was a document with multiple instances.