Dataviews exported to Excel, that contain date cubes, do not behave as 'normal' excel users would expect. The dates are exported as TEXT, not dates.
When an excel filter is added to column headings, the date column lists the dates in text order (not chronologically - eg 01/04/2018, 04/01/2018, 08/12/2016 etc)
When sorting the excel spreadsheet, the option 'sorting text as numbers' has to be used to sort the date column correctly.
My idea, would be to implement additional options in 'Export to excel' which would accommodate date data (as numbers formatted as dates, rather than text displayed as a date).
Perhaps there are further functions required for 'Export to excel' - currently there is only 1 option (in Web) whilst in Desktop there were several.