1. enable all WIReportServer(s) tracing and set Log Level to HIGH to captures all critical message into log files
2. monitoring the Metrics of each WIReportServer and look for the "Number of documents" and/or "Current number of sessions" for scheduling and view/editing session, respectively, greater than 1
3. Open the tracing log file, such as webiserver_WAPPxxxxx.WebIntelligenceProcessingServer_trace.000001.glf that has activities on "Number of documents" and/or "Current number of sessions" and comb through the log for document name and user id.
Note that if you have "Enable Memory Analysis" unchecked like me, the WIReportServer will try to grab all available MEM from the OS until it cannot.
Regards,
Jin-Chong