Thanks for the post. The TestRail: Results tab will show the results of any TestRail entity that is linked to that issue. The For Tests tab shows results where the issue has been logged into the “Defects” tab of a result, while the For Runs and For Cases will show the relevant results of Test Runs and Test Cases that are linked to the issue via the “References” field for those entities. In the example you provided, this indicates that the test case titled “Account Suspension Email” has this Jira issue linked in the references tab, and is showing the results of where that test case has been included in a run. The “For Tests” tab is blank because no tests were directly linked to this issue using the defects field during test execution.
I do see that the “No cases are linked to this issue” wording may cause additional confusion, and I’ll pass that along to the team to see about updating the language to provide further clarity.