Contextual filter shows duplicated nodes

Hi, I am using contextual filter in a view to show nodes of a content type that has a certain field value.

The problem is that sometimes the view shows the same node several times (two, three, four or even more).

I've tried with the SQL settings distinct option checked, but doesn't work. I've seen solutions to this problem for people who work with taxonomy, but my filter works with a field value, and is showing the same node many times.

Please help!