I've noticed several times that when printing a large number of vector drawings, individual elements can start to go missing.
Example: I'm printing 5 sheets with 35 buttons per sheet (each button is an identical logo made up of grouped lines and shapes), and half was through the print a line or two will go missing from a few of the buttons. Then the whole logo is gone and the printer starts spitting out blank pages. MAKES PROOFING VERY DIFFICULT WHEN I HAVE TO CHECK FOR EVERY LINE!
I don't know if this is part of the same issue, but occasionally when printing single-page proof layouts, I have several objects that go missing on the printed page. (Usually after working on a large number of different files throughout the day.)
Closing and then re-opening Corel has been my fix for this.
I am assuming that it has something to do with an internal cache somewhere being full, so closing & re-opening resets that cache.
That is just my own theory, though. I hope it helps.
That might make sense!