Kubernetes e2e test is not stable

The output file is: https://dev.azure.com/apache-flink/apache-flink/_build/results?buildId=51444&view=logs&j=bea52777-eaf8-5663-8482-18fbc3630e81&t=43ba8ce7-ebbf-57cd-9163-444305d74117

Jul 19 17:06:02 Stopping minikube ...
Jul 19 17:06:02 * Stopping node "minikube" ...
Jul 19 17:06:13 * 1 node stopped.
Jul 19 17:06:13 [FAIL] Test script contains errors.
Jul 19 17:06:13 Checking for errors...
Jul 19 17:06:13 No errors in log files.
Jul 19 17:06:13 Checking for exceptions...
Jul 19 17:06:13 No exceptions in log files.
Jul 19 17:06:13 Checking for non-empty .out files...
grep: /home/vsts/work/_temp/debug_files/flink-logs/*.out: No such file or directory
Jul 19 17:06:13 No non-empty .out files.
Jul 19 17:06:13
Jul 19 17:06:13 [FAIL] 'Run Kubernetes test' failed after 4 minutes and 28 seconds! Test exited with exit code 1
Jul 19 17:06:13
17:06:13 ##[group]Environment Information
Jul 19 17:06:13 Jps