I loaded 100 pages PDF into Okular. Needed only even pages so chosen File->Print, selected "Print all" and then "Even Pages" as Page Set. After several minutes of 100% cpu time and frozen UI I got 100 pages resulting PDF file. I expected 50 pages file with only even ones. Version: okular-16.08.3-1.fc25.x86_64
*** This bug has been marked as a duplicate of bug 252596 ***