I can see how that would cause a problem. However, I think the difference with my problem is that I have built my survey completely on survey123.arcgis.com. I did not use the Connect where you have access to a form like in your image.
In the online survey, I changed the text in a description field and two words in one of single choice field. I did not change field names. I also did not change anything in the schema—that option is locked after a survey is published. On July 1st, I made more complex changes to the survey and added questions (fields) and was able to publish with no issues. I'm wondering if this is a bug in the new 3.0 edition...?
I will pull the survey into Connect to see if I spot anything like you mention.