When exporting comments from one PDF to another, sometimes they are imported to the 2nd PDF off by 90 (or 180, 270) degrees. I think the issue is when the original user (my customer) who creates the PDF doesn't use the same program to create PDF1 and PDF2, but I haven't been able to confirm this. A feature to allow me to control the orientation of all comments regardless of page size (comments would always fit to the page size) from PDF1 to PDF2 would be a huge time saver. It would also save the hassle of me bothering my customer to re-format their PDF.
Adobe Acrobat Pro DC
Win10