The version gadget looks like this.
The "By" value is wrong; I've never edited this page.
The "Publish"-button, however, has the right author.
Note the same date and timestamp as the latest version in the image above.
Looking at the api call to /login/cms/stores/contentversion?contentLink=[pageid], the json response for some of the versions of this page has the wrong "savedBy" value, but correct "statusChangedBy" value.
Others have also seen this bug:
As I said in the thread you mentioned, it was a bug and was fixed but not released yet (will be in EPiServer.CMS 11.15.1)
Thanks for the update!