The issue is really minor - invert=1 in url will not affect UI and cannot be saved as a part of saved filters.

1. On RC page select any filter (s).
2. Click on Namespace filter button and without selecting any namespace, click on 'Exclude selected'. The button becomes active and invert=1 is added to the url.
3. Click again on 'Exclude selected' - it becomes inactive, but url would still have invert=1.