TestScanMemLimit.test_hdfs_scanner_thread_mem_scaling fails intermittently

query_test/test_mem_usage_scaling.py:376: in test_hdfs_scanner_thread_mem_scaling
    self.run_test_case('QueryTest/hdfs-scanner-thread-mem-scaling', vector)
common/impala_test_suite.py:776: in run_test_case
    update_section=pytest.config.option.update_results)
common/test_result_verifier.py:682: in verify_runtime_profile
    % (function, field, expected_value, actual_value, op, actual))
E   AssertionError: Aggregation of SUM over NumScannerThreadsStarted did not match expected results.
E   EXPECTED VALUE:
E   3
E   
E   
E   ACTUAL VALUE:
E   1