Regarding documentation at https://ds_infolib.hcltechsw.com/ldd/lcwiki.nsf/dx/IBM_Connections_4.0_Metrics_Frequently_Asked_Questions
... Read events originate from Connections Desktop Plugin are currently NOT tracked by Metrics (limitation confirmed by L3 support).
Create, Update, Delete (CUD) events originated from Connections Desktop Plugin are already tracked by Metrics.
Now, for tracking of read events, Connections Metrics provides the Read Event Tracker API: https://ds_infolib.hcltechsw.com/ldd/lcwiki.nsf/dx/Metrics_Read_Event_Tracker_API_ic60
Looks like that Connections Desktop Plugin needs to be enhanced to make use of this API.