Have you checked the settings for each person's access level? At the bottom, in the section called "Allow Administrative access for....", there is a check-box for "Timesheets and Hours":
This allows people to view ALL hours and timesheets in the system. Without this option, people will only be able to view hours on:
- Projects, tasks or issues they manage
- Their own timesheet
- A timesheet of someone that reports to them
- A timesheet they approve.
Another option may be to change the report settings to run with the access rights of one of the users who is seeing all of the data correctly.