It is just so fun when you have @ as a lead character for fields. You can do DATA-IMPORT from CSV and it is fine but if you just double click load a CSV from explorer it tries to interpret the data as a formula and randomly loses the @ I have not check myself the full list of special characters that cannot be loaded CSV style from Explorer but one should expect consistency with DATA-IMPORT functionality
In a CSV with zip codes, Excel drops the leading zero: Boston, 02114.
A CSV with text ranges: 1-10, 11-20, 21-30... becomes 10-Jan and 20-Nov!