We have seen old posts on this error with QF Server and the Document Preview services (links below) but we did not see a resolution for either of those and now we are getting it with the newly released AI service for self hosted systems. When we get this error the document is never processed by Smart Fields. If we run it again then it works so it is not related to the document itself. I think it is still related to whatever caused it with older versions of QF Server and Document Preview.
Error message from event viewer:
No MediaTypeFormatter is available to read an object of type 'HybridJobErrorDetails' from content with media type 'text/plain'.
https://answers.laserfiche.com/questions/141810/Error-when-pubilshing-session