Not sure which version this started with, but happens in 9 and X for sure.
When printing a document, usually if you went into the printer properties and changed the paper size, after clicking OK the preview in the Reader print dialog box would update to the selected paper size. Now it doesn't. If you don't click and change some other option then the selected paper size never displays and the wrong page size prints out.
Users find it frustrating because some don't look at the preview, just hit the print and 100's of pages print out on the wrong size paper.