Cannot change the default view for gauges from Portal on a homepage. Setting it to "empty" (the name for "default") sets it to portal. If you try to type "default" into the view, you generate a new view with the name "default".
The view for gauges on homepage is set to the Portal view. You can change the view on a gauge; however, to set the view to "default," you need to set it to empty (the name for default is empty). Because on gauges an empty view is "portal", there is no way to set the view on a gauge to default.
Beginning with the Jakarta release, the glide.ui.gauge.view system property enables admins to define which view to use for the default of homepage gauges. Consider upgrading your instance to at least the Jakarta release to access this property.