Peter B., would you mind sending us your XML files that define the properties, settings, and strings, as well as the <app name>-settings.json that gets generated alongside the PRG? We can try to reproduce the error using these files. You can send them to [email protected].
Peter B., the JSON file you sent is not formatted correctly. I ran it through https://jsonlint.com and there are several errors with it. It looks like the text is getting escaped in places it should, with one example being the configHelpUrl value. I'm not sure if that happened on your end or ours, but I used the XML files you sent to regenerate the json file using the 4.1.beta and it is formatted correctly. Can you try again using the latest beta SDK?