Results of all the tests are not shown for a candidate

A candidate can always continue the assessment where he has left off - they don't need to take all the tests at once. Whereas they cannot take the tests that they have left incomplete (Candidate closing the browser, forfeiting the test, power-cut issues, or by malpractice auto-forfeit). So, if the platform shows you that the candidate has already taken it but shows no results, it probably means that the candidate has started a test and didn't complete it, for some of the above-mentioned reasons.