I have a requirement similar to this. https://www.sharepointusecases.com/2010/01/creating-filtered-lookups-in-sharepoint-2010-with-infopath-2010/
In my case Project field should be a text field and auto populated based on "TRUE" OR "FALSE" value. So what I have done was created similar InfoPath form and additionally created one field for "TRUE" OR "FALSE" and one field for Project text field. I set a rule to Project dropdown field, when Project dropdown field changes set Project text field value. Problem is only when I select Project dropdown field, project dropdown value is loading. Otherwise project dropdown value is not loading. Any guessing what's going wrong?