ALV / Download to Excel -> columns transposed

A developer on my team has this problem:

We have a ALV report that gives the user the option to download to excel.

The report has columns.

A,B,C,D (for example)

but when the user exports to excel ("List > Export > Spreadsheet > Table")

they get

A, <b>C, B</b>, D

Dose anyone know why this happens? We have checked various sites and found OSS note 358644.

Are we on the right track? Or is there an easy answer to this.

Thanks in advance.