Check what Requirement Coverage Strategy is selected:
If "Use versioned Test Sets for Requirement Coverage" is selected, only Tests within Test Set with Fix Version assigned will be considered for coverage. (Showing with N/A status if added to a Requirement)
Check if a workflow status in the
If a workflow status is selected in this option, all tests with this workflow status will not be considered for Test Coverage calculation. (Showing with N/A status if added to a Requirement)
Adjust the configuration to include or exclude the Tests within the Test Coverage calculation as you see fit.