As far as I remember, up to some past version, if you suspended or buried a card in a filtered deck, it would leave the filtered deck. It seems it is not the case anymore. I can’t see anything related to this change in the change log so I wonder whether it’s an accident or whether it’s intentional.
In any case, it was counter intuitive to see a filtered deck which indicates no card due and that still shows a warning when I want to delete it.