A month or so ago I did a test migration of a few on-prem TFS projects to Visual Studio online. For the most part everything worked. Changesets were migrated over showing the same check-in user as on prem with a comment showing the original checkin date, user and changeset id. Same with workitems, I'd review the history and I'd see entries like "User1 (via MyUserACcount)".
Yesterday when I tried another migration I don't see any of the above. All the changesets show as my account with no migration details in the comments and the WorkItems only show me in the history.
Has the recent updates to VSO broken something?