CorelDRAW X8 -Issue with mitered corners when publishing PDF - Help!

Hi, I'm new here. I've recently upgraded to X8, and having an issue with box shapes. There's no miter applied to the shapes, however when publishing a PDF it applies random miters. Is there any fix for this? I have tried setting the miter limit to various sizes with no success. Anyone else had this issue?

See below post for screen shots...