I have a situation where I am trying to run a String through a service (not important which). Specifically, I am attempting to dynamically apply a String to msg.payload and then the service reads this (and does something) - however the service doesn't like the format when I do this dynamically (e.g., msg.payload.body). The crux of the problem seems to be my understanding of Strings in Node-Red, i think. See below the two different outputs I get (one with an arrow drop down) and one without. Is someone able to explain to me what the difference is?