Permissions cannot be modified after QMM has beed used to migrate users and groups (4349092)

Permissions cannot be modified after QMM has beed used to migrate users and groups, when migration was performed within the same forest and  the sid history was added to target objects.

This seems to be a known issue and is expected. Microsoft doesn't recommend to migrate with sid history when performing an intra-forest migration and doesn't support a scenario, when they same sid appears twice within the same forest.

It has been observed in the field that when looking up the permissions this might now work properly. Example: when you look up the ACL’s on a share or on the files and when the SID’s are being resolved, and then a duplicate is being found in the forest, then enumeration will stop at this point and will not continue.

This makes the (manual) managing of permissions nearly impossible.