I’ve come across an occasional bug in printing with OO. Sometimes when I go to print a document, the print dialog has a save button rather than a print button. And if I absent kindly click the button, it brings up a second dialog offering to save the file, rather than sending to the printer.
Clicking cancel and attempting to repent only gives the same problem. The solution is restarting OmniOutliner.
The bug is happening on macOS Sierra and OO 4.6.1 … not sure if it happened with El Captain.