"Merged by" sometimes empty after update to 12.10.11

Hi everyone!

Since a recent upgrade to 12.10.11, on most (but not all) merge requests the “Merged by” field is empty. We have tried to reproduce the issue, but weren’t successful.

The only difference in the affected project(s) is that permissions are not granted by adding individuals, but by adding other groups instead.

Describe your question in as much detail as possible:

  • What are you seeing, and how does it differ from what you expect to see?
    We’re seeing almost all merged merge requests with no user information after the “Merged by” string.
    We would expect so see the actual user that merged the MR after the “Merged by” string.
  • Consider including screenshots, error messages, and/or other helpful visuals
  • What version are you on (Hint: /help) ? and are you using self-managed or gitlab.com?
    12.10.11 (171498bd025) community edition, self managed
  • What troubleshooting steps have you already taken? Can you link to any docs or other resources so we know where you have been?
    We assumed that the issue may be correlated to the background migrations after update, but we couldn’t find a job that would fit. No other measures have been taken.