Using version 1.3.1.000 of the OpsHub Visual Studio Online Migration Utility I successfully (556/556 changesets/labels, 0 retry) migrated a project to VSO. To validate the process I did a file comparison between a fresh Get Latest of the project from TFS and VSO and found differences.
Here is the history on the file that was different:
TFS
VSO
It looks like your utility did not correctly handle this change. Is this a known issue? Is there anything I can do to get around it?