For clarity (I needed it), Google Forms won't populate a question that has duplicate ANSWERS. So, if the column in your sheet has the same value more than once, Form Ranger will faithfully pull the data and show it in the preview but Google Forms will not populate the question. Because my data is such that duplicates are pretty unlikely, I just selected the range that was giving me problems, clicked "Data" and selected "Data Cleanup" and then "Remove Duplicates. If you are set up for Form Ranger to automatically update the questions in your form, or data is more susceptible to duplicates (like an attendance list where someone might accidentally register twice, for example) you can set up a filter in your sheet to automatically remove duplicates so that you never have to worry about questions in your form going down without your knowledge.