Mass Update "Assigned To" access for regular users

I’ve run into an issue that I can’t seem to fix.
I have a custom module I made which makes use of the “assigned to” field. This module’s data is maintained by non-administrative users. One of the tasks they have is to mass update records to set the assigned user field.

The issue that I’ve run into is that I can’t seem to find the proper access for them to be able to do it. They always get the “You do not have access” message when they go to save.
I went into the roles and gave the following access:
customModule : Mass Update (All)
Users/Security Groups: View (Group), List (Group), Edit (Group)

Is there a permission I’m missing? When they go to mass update they see the list of users. Its when they select the user and click save that they get the error. I did notice that only the user’s record in the list has that link colour where the name is. The rest are just regular text.

Try to Repair Roles from Admin -> Repair.


Unfortunately that didn’t make a difference.

Your user does not include into one Security Group.
I recommend make special role for Mass Update user:
Mass Update: all, Edit: all .