Facet: select 2 items from single facet returns to many results

[Mojster]

Hi,

In render we've got a "host" facet. After selecting an facet item (item(3)), I've get 3 results. After that I select an additional second item (second item (2)) from the same facet, I presume I should get a sum of results. So this would be 5 items. But instead I get 61 result.

Is this a bug or is it my mistake in configuration?