ChatOps fails to trigger a CI job (silently)

Summary

During the 18.4 hot patching practice, I noticed that ChatOps sometimes fails to create a CI job. There is no indication of failure in Slack which is confusing.

Slack log	GitLab CI pipelines
Note the two messages in Slack at 11:26 and 11:39. There are no corresponding pipelines in Gitlab CI for these messages. In fact, there were no ChatOps pipeliens between 11:11 and 11:41

All times displayed in the screenshot are (UTC+9)

Exit criteria

• Find out from other team members if this is common / expected
• Find out if there are any other ways to notice that ChatOps is not creating pipelines
• Document, if possible