A manual undo finds the correct address to use:

Reverting a user also displays this internal IP, instead of the username:

locally, the user param from the mysql queue can be treated directly like a userIdentity. in beta, we get a serialized json representation of that object so we get the user from the global request context. In the production jobrunner, one of those two sources (the job param or the request context user) is set to this internal ip address rather than the user who initiated the original request. We set the job params in our hook implementation, so I'm going to set it to change it to the uid which should let us avoid any of these serialization/request context complications. It will add a db lookup to the job, but those are running async so it should not be an issue.

Change #1035803 had a related patch set uploaded (by Jsn.sherman; author: Jsn.sherman):

[mediawiki/extensions/AutoModerator@master] [WIP] use correct username in edit summary

https://gerrit.wikimedia.org/r/1035803

Change #1035803 merged by jenkins-bot:

[mediawiki/extensions/AutoModerator@master] use correct username in edit summary

https://gerrit.wikimedia.org/r/1035803