If detailObject.jsp file is configured to not crawl Attachment files, then Knowledge Documents with Attachment files are not crawled.
By following technical document TEC1344438, new Documents created after the change will not be crawled if they have Attachments.
You need to run the Incremental Crawl after the Initial Full Crawl. When you add a new document, you need to run the "Incremental Crawl", not "Full Crawl" as shown below.
- Reset Index on the SharePoint server.
- Run the Full Crawl.
- Run the Incremental Crawl.
- Create and publish a knowledge document with an attachment.
- Run Incremental Crawl again.
TEC1344438: How to stop crawling attachment files for the Federated Search function (SharePoint integration)?