− is an HTML entity name for the mathematical minus symbol which most people also use as a dash. If this is appearing in export, I’d guess that the Manager database either stores ‘-’ as
− or replaces occurrences of it when parsing data for output in HTML (what is needed for the day-to-day use of the application). Perhaps the same parsing happens for export?
This is pure speculation on my part of course. I don’t know anything about the backend workings of the application. However, sorting out exported data in Excel should be a quick and simple matter of using Find and Replace to change all occurrences of
− with a dash or minus character. Admittedly you’d need to do this for every export until the problem is resolved but at least you don’t need to change things on a line-by-line basis.