This issue occurs still in Oracle after
1. Create a regular role
2. Click on Actions -> Define Permissions
3. Select Communities from drop-down list
4. Check the Actions "Approve Proposal", "Assign Member" and "Manage Pages"
5. Click on Save
6. Again select Communities from the drop-down list
7. Limit the scope of all selected actions to guest community
8. Click on Save
The permissions list shows the mentioned actions for the scope "Guest"
Only one permission "Approve proposal" for communities is listed with scope "Guest"
Is anyone able to reproduce this behavior?
Thanks in advance and have a nice working day,