Survey export-responses API failing to return response values

I'm using the Qualtrics `/API/v3/surveys/{surveyId}/export-responses` API with the `"format": "csv", "useLabels": "true"` parameters. There is a multiple choice response option in my data of 'None=1' and these responses are being excluded from the API export and simply showing up as empty values. In other words, within a side-by-side question with multiple choice answers of `1 None,2 Mild,3 Moderate,4 Severe,5 Extreme,888 No response`, all responses except for ‘None=1’ (and 888, which uses the ‘excluded from analysis’ option in the survey) are being returned with the data. If I manually download the data from the web application then the 'None' values appear in the data. I did not find any exception in the survey template that point to a reason why the 'None' values should be excluded from the data. The only portion of the survey template with an explicit exclusion are the `888` values.

Is this a known bug in the API or is there some other reason this data is being excluded from the API request?

I should note that the 'None=1' response option does NOT have the `exclude from analysis` option selected for it. 

thank you