By accident (not having defined XLSX_DATE in settings.py) during xml export I encountered a bug in the exception code, showing an error message that "request" was not defined:
except: messages.error(request, "Unexpected error ....)
1) remove message.error() lines from the export functions
2) pass the complete request object as first parameter to the export functions in exportviews.py instead of request.GET
Personally I think option 2 is best; do you agree @edmcdonagh ?