Github user StefanRRichter commented on the issue:
https://github.com/apache/flink/pull/2706
At least at on the first checkpoint was the only time I ever observed it.--- If your project is set up for it, you can reply to this email and have your reply appear on GitHub as well. If your project does not have this feature enabled and wishes so, or if the feature is enabled but not working, please contact infrastructure at infrastruct...@apache.org or file a JIRA ticket with INFRA. ---
