Exporting a Survey123 for ArcGIS survey from ArcGIS Online fails consistently when the option to export as a file geodatabase is used, but works when exporting as a shapefile.
This issue is not reproducible in the current release of the software. If you are encountering this issue, please contact Esri Technical Support (for customers in the United States) or your Esri distributor (for customers outside the United States) to resolve this issue.