Some spreadsheet programs do not retain emojis in titles after exporting a spreadsheet to a CSV file. When this occurs, emojis appear as question mark icons instead.
Solution
Export your spreadsheets using Unicode (UTF-8) encoding rather than standard CSV format.
Platform-Specific Instructions
Microsoft Excel
Use File > Save As and select CSV UTF-8 (comma delimited) (*.csv) -- specifically the UTF-8 variant, not basic CSV.
Apple Numbers
Choose File > Export To > CSV, ensure Text Encoding is set to Unicode (UTF-8), then save.
Google Sheets
Access File > Download > Comma Separated Values (.csv). Google Sheets files are automatically encoded in UTF-8, so emojis should import properly.