I have come across something that I think must be a bug, or else I'm missing something vital.
On a fresh 2.3.3 installation with the BlackCandy theme, I log into the CMS, make some changes to a page and hit Save and Publish.
If I now look at the Page Version History my newly created version is listed there but the Author and Publisher columns are totally empty.
If I look into the database in the SiteTree_Versions table I find TWO versions of the same page I just created (one with status Save (update) and one with Published - is this correct?). The page with the Published status gets PublisherID = 1 but AuthorID is 0.
The same happens if I create a new page.
Even though the PublisherID is set to 1 (that's the default admin account, i.e. me) the Publisher column is still empty under Page Version History.