I think your regional settings are in ISO format (2017-03-17) and in your CSV file dates. It looks like 27-03-17 when such data will be recognized as one in the year 2027.
Since Excel considers the CSV data as one with 2-digits year format i.e YY-MM-DD.
I guess since not clear how dates are formatted within the CSV (text) file. You must try to fix this issue by using Excel formulas to change years and dates.
Check out the following fixes to resolve: Excel Not Recognizing Date Format