I see one unusual thing: In the detail band, column object a_linjetekst1 and computed field cp_krredit both have their "Slide Up" (on the Position tab) property set to All Above. I cannot see any reason why Slide Up should be set this way. Try setting to None for both objects and see if that makes any difference.
I note that in the Data Export tab for the DW properties, the export method is set to Distill!. You might wish to see if setting this to NativePDF! makes a difference.
I also notice the DataWindow's version is 11.5. There's nothing wrong with that, but you might also try making a minor, inconsequential change to the DW, and saving it (to force PB to update the source syntax) to see if that makes a difference. Of course, changing the Slide Up and/or export method properties will accomplish this as well.
If there is no change in behavior, you'll probably want to report this as a bug.
Best regards, John