A message post migration is missing any embedded OLE content ie. embedded table. The space where the content is supposed to appear is blank in the migrated mailbox.
This issue is caused because the Microsoft RTF converter is not processing the content properly.
To resolve this issue, please add the following to the Data Migration ini file in the [Exchange] section:
RewriteRTF=0
Then attempt the migration again to see if the issue is resolved. Note that to re-migrate the message, the existing target message must be deleted first.