This is a long standing bug in the "Send to OneNote" printer driver and it's about time that Microsoft solves it. Sure, there are numerous workarounds one can use to overcome the problem, but the bottom line is the orientation of the document needs to be
automatically detected by the OneNote printer driver.
To illustrate why this has to be solved by Microsoft, consider the following scenario: a MS Word document contains to sections, the first section is in portrait orientation and the second in landscape. If you print this document to PDF using the "Microsoft
Print to PDF" printer driver the result is a PDF where all pages are in the correct orientation.
To print a PDF to OneDrive is no different from printing an MS Word doc to PDF. As such, it is puzzling that Microsoft are able to do this correctly in their PDF driver, but not the print to OneNote driver. You'd think that if this got to the correct folks
within Microsoft they could fix it in a heartbeat!