Menu item always saved with default XMLsitemap setting

This seems to be a bug: I have XMLsitemap Menu enabled, and set the default xmlsitemap setting for Primary Menu to Excluded. The settings warn that Changing these type settings will affect any items of this type that have either inclusion or priority set to default. In my case, this should be no problem. But:
When I change the settings for a specific menu item, e.g. 'Included' with a Priority other than the default priority (it's a bit confusing that with default: exluded there's still a default priority) and save this, the change is not actually being saved, or it is being reset to the default: when I edit the same menu item again, the setting for the menu item is set to 'Default (excluded)' again.

The specific menu items I want to include are Views menu items (but that shouldn't be a problem? Since with Default: Included they are added to the xmlsitemap just fine).
Or maybe I want the module to do something it isn't meant to do? But then documentation should be added saying that overriding the default is not possible for menu items.
For now I'll use Custom Links, but it would be nice to get this working.