Hi,
It seems to be an OSX specific issue as we are also able to reproduce this here on Yosemite but not on Mavericks. Are you running the latest version of Yosemite? Do you have access to an earlier version of OSX for testing purposes?
We have also found similar issues regarding the PDFView in native Mac applications as well, so the issue is not related to Delphi. We will further investigate this here.
Kind Regards,
Pieter