Help Needed: Issues with HTTP API Post for PhoneBurner Training

Hey all, I am new to Clay and looking to create some training for PhoneBurner customers so they can start feeding data into the PhoneBurner system using an HTTP API post. I am running into an issue and getting an error related to a Failed parse body input when I try to merge data from another column into my payload. When I remove the merged data I am able to successfully POST a new record to the system. I was able to successful merge data in another attempt. Anybody know what I am doing wrong here?