nav 4.0 SP3 report, pages mix

We need to print a letter and send it to 3500+ recipients. Their addresses stored on the same dataitem record.

The letter consists of 2 pages. A dataitem is made with 2 body sections with sizes to match 2 A4 pages.

The letters start printing well at around 80 pages but then they mixup, the 2nd page is printed first and the 1st page is printed second. After 100-200 pages the sort is corrected and then reversed again and so on. This is a problem because we print each letter double sided and on the first page there is a letterhead.

Printing fewer each time doesn’t resolve the issue. This happens from the Preview before getting on paper.

I hope you can understand the issue.

Thanks in advance!