Hi Lluís,
If you only have one item in the filter, then I would rather recommend using the advanced options to include items from that category – that way you don’t have to use that filter at all, since I am guessing you only want to restrict results to a specific category?
If you wish to use that filter anyways, then maybe changing the keyword logic to this: https://i.imgur.com/5sfEWKa.png
..as well as turning this option off: https://i.imgur.com/aRmi6AZ.png
