Thanks for looking into this. I just tested using your steps and that is indeed what the issue is.
I cannot figure out how those text items got "?" for their rotation.
I tried:
- reimport sheets
- import vector pdfs as sheets
- transform by points
- move
- project cleanup
- convert to linestring
- explode
None of these seem to reproduce the issue.
I will have to keep an eye on this but at least i know what the cause of the error in the export is now.