This might be because the user should not have permissions to change the configuration of non-instanceable portlets in a customizable column.
Steps to reproduce and test:
- As Admin: Create a page1 in Site1, and set as customizable the column on the right
- As Admin: Add the wiki portlet to the default view of the column on the right
- As Admin: Create user1 and set as member of Site1
- As user1: Customize the configuration of wiki portlet.
Results: Admin user view the wiki customization of the user1 in the default view, and also in his view.
Expected: Customization of user1 in the wiki portlet doesn't affect to other users.