Question Why are there more columns than headers in CSV data files?

Every second, the NMEA strings, delimited by single quotation marks, are included as separate columns. The strings also contains commas. Therefore, there will be more columns if you use comma as the only delimiter.

The correct import setting should be comma-separated, with single quotation marks as string delimiters. All of those "extra" columns will be revealed as the original RMC and GGA NMEA strings.