A user can see call records not owned by the user on Online My Schedule Page. However, the user cannot open the call records from My Schedule Page.
One possible reason is that the user is added as an attendee in a group call by other users and then this call shows up on the user 's My Schedule page.
If the user wants to see the call details, the user should be granted access to the account associated with the group call.
CRM Help Documentation: N/A