If you are in one part of the hierarchy when you build a list report to bulk edit, the options to bulk edit the assigned to user will be determined by the workspace you are within even if the results are from other workspaces with different permissions
You may not be able to update the assigned to user to the desired user if they don't have permission on the workspace you are in, even if the filter set is for data from different workspaces
The permission check for what assigned to users are eligible for a bulk edit should be determined by the records selected for bulk edit regardless of where you are when you take this action