End user can go to the Configure option and select the 'Restore Defaults' button from the General page to restore filter to the default view.
Go to the Project portlet Filter section, select the Manage Filters dropdown to inspect/remove corrupt filter. - When a user creates their own user-defined 'default' filter, it is a saved filter that will always be used as the default. To remove this personal, saved filter, the user can select the filter and click on Delete button to restore System Default as the default filter. The user can then log out of the application and the next time the user logs in, the System Default filter will be used for that portlet or list view.