new refiner in peopleresults.aspx

I followed this guide to add a refiner for peopleresults.aspx

The idea is that there is a list where a taxonomy/metadata field from the term store that accepts multiple values is matched with a user.

The property is mapped correctly so that a content search web part displays correctly the refinablestring01 content.

The refiner in peopleresults.aspx does not give any result. The only difference I have with the guide above is that my value is multiple choice instead of single choice.

What am I doing wrong?