So there was nothing for me to do.
Oh, there was a case of "duplicate customers created by one user, 1.5 minutes apart. There were two cases for that; the cases were duplicates, so Valery closed one. I closed mine (derivative), but then reopened, and asked around if anybody can help with investigating. Since the logs had entries like "event message successfully processed". That's it, no request id, no details what was it. Chinese programming, I would say.
But then Valery answered my question. Yes, two customers were created because the user did it. And the user did it, because the first creation attempt was reported to him as failed. So, was not it natural?
I tried, at the meeting, to discuss this case, and turned the investigation into "why t.f. do we report a failure if a user was created", but there was no time for that. Everybody was discussing the weather: Asheville and the areas around, badly damaged by the hurricane.
Later, after the meeting, I was still pushing through that little thing, "new error messages", and merged, but then a format was not followed (no tools report bad yaml format for this project), so I updated that shit and sent for review again.
What should I do now? Nothing.
But I'm on alert.