I feel like I should reply to my own post one last time in case anyone sees it and is misled. There was in fact nothing wrong with the script. There was something in the object style that caused it to fail with a particular paragraph. I never did find the wrong setting, but by using the object model directory, https://www.indesignjs.de/extendscriptAPI/indesign-latest/#Application.html, I was able to build up the object settings line by line, and then create a new object style out of the finished result.