Created attachment 117686 [details]
When 'export to PDF' is used, if 'PDF/A' format it selected then - even if printing an entirely blank page - a spurious error message is generated as per the attachment.
i can confirm.
it should be possible to supress this message, e.g. set an option like
Tools - Options... - LibreOffice - Print - Printer Warnings "Transparancy"
and this message should not appear at all if export is triggered via api calls.
*** This bug has been marked as a duplicate of bug 65439 ***