If a View record is marked as Hidden, it will still be viewable to non-admin users if the currently selected View is Default, until the cache is manually cleared.

1) Log in as any admin user
2) Go to any List (Example: /incident_list.do)
3) Right click on the header -> View -> Note one of the non-Default views. (Example: Portal)
4) In the navigator, type in 'views'. Click System UI -> Views
5) Locate the record from Step 3.  On the record, click the Hidden checkbox and Save.
6) Impersonate any non-admin user (Example: Abraham Lincoln) and navigate back to the List from Step 2
7) Right click on the header -> View -> The selected view will be the one you just hide.  

If you select another non-Default view then the hidden view will not show up to be selected, but if you select the Default view then the hidden view show up as selectable until the cache is manually cleared.

This problem is currently under review. You can contact ServiceNow Technical Support or subscribe to this Known Error article by clicking the Subscribe button at the top right of this form to be notified when more information will become available.

To workaround the issue, navigate to cache.do to manually clear the cache.