Alteryx takes the field type for QVX files from the QVX file itself. If you open the QVX file in a text editor then there is a section of XML at the top which defines the fields.
Each field should have a section like this
Are you able to share the XML for the field you are having an issue with? (Presuming you are unable to share the entire file)
Principal Software Engineer
Tech Lead Core Engines, Alteryx