Embedded data based on URL parameter

Hi all,
I am struggling to set embedded data field value based on whether a URL contains a certain parameter.
I am using a Referer and Q_URL fields and want to set up embedded data based on, e.g. if the URL contains word "product" in it. The link is recorded correctly, but the Embedded data field is not populated. I use the following logic in the Survey flow:
I tried recording the value of the Referer / Q_URL in another ED field "Link1" and tried to set the value from that field, but it is also not working. The Link1 field is populated with the correct URL, but the ED field i try to fill in is again empty..