I have created a project for testlink/jenkins plugin tutorial.  The TestLink results in Jenkins shows, TestLink history states test case has never been executed:

TestLink Results

 
-------------------------------------------------------00:01:05.506 T E S T S*00:01:05.506* -------------------------------------------------------00:01:05.877 Running jenkins.plugins.testlink.examples.TestCurrentTime*00:01:05.974* Configuring TestNG with: org.apache.maven.surefire.testng.conf.TestNG652Configurator@64a294a6*00:01:06.515* Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.624 sec*00:01:06.754* 00:01:06.754 Results :00:01:06.754 00:01:06.754 Tests run: 1, Failures: 0, Errors: 0, Skipped: 0*00:01:06.754* 00:01:06.754 [INFO] ------------------------------------------------------------------------00:01:06.754 [INFO] BUILD SUCCESS*00:01:06.754* [INFO] ------------------------------------------------------------------------00:01:06.754 [INFO] Total time: 59.610 s*00:01:06.754* [INFO] Finished at: 2017-08-07T12:10:58-04:00*00:01:06.755* [INFO] Final Memory: 144M/344M*00:01:06.755* [INFO] ------------------------------------------------------------------------00:01:06.814 Executing iterative Build Steps.00:01:06.814 00:01:06.814 Looking for the test results of TestLink test cases.00:01:06.814 00:01:06.814 Looking for test results in TestNG suites by its name.00:01:06.814 00:01:06.903 Found 1 test result(s).00:01:06.903 00:01:06.949 TestNG Reports Processing: START*00:01:06.949* Looking for TestNG results report in workspace using pattern: target/*/testng-results.xml*00:01:06.971 Saving reports...00:01:06.980 Processing 'C:\Program Files (x86)\Jenkins\jobs\Jenkins TestLink Plug-in examples\builds\657\testng\testng-results.xml'00:01:06.981 TestNG Reports Processing: FINISH*00:01:07.398* Finished: SUCCESS