Audit Log doesn't show permission changes

Steps to reproduce:
1. In RM site create a category
2. Hover over the category created in step 1 and from action menu select "Manage Permissions"
3. In "Manage Permissions" screen click "Add User/Group"
4. In "Search" text button type "ALL" and click "Search"
5. In any group row (such as "All Records Management Roles") click "Add"
6. Click "Read Only" and from dropdown menu select "Read and File"
7. Click "Save"
8. Repeat step 2

Expected: Permission change is shown in the audit log.

Actual: Nothing is recorded in the audit log.

Note this is just one scenario, identical results happen when changing permissions on folders or records as well as getting a full audit log in RM Admin Tools.