Dynamic Fields Not Working

I am trying to create a dynamic field, and having the same problem with both iframe and URL types.

In Studio > Fields i am using “Generate URL” to add the dynamic fields to a default value for the field. When viewing the field in DetailView the iframe is displaying properly, but the link is not passing any dynamic content. instead, the variable is in the link, still in curly braces



does anyone know if i am doing something wrong, or if there is reason why this is happening?