The best solution for this issue is not to run the SID History report. In a case where this report is needed, you may run the report and then delete all of the user objects from the migrated objects table. Group objects are still needed for group membership update.
Editing DMA's databases is not a supported action, but is only suggested as a workaround for special cases. Please test this and all unsupported workarounds in a non-production environment before implementation.
This information is also available in Chapter 8 of the DMA 7.1 User Guide.