I know this is a fairly old topic, but I have seen this problem of the wrong PDF DOCUMENT showing up in a browser window recently. If I run a first DISPLAY DOCUMENT, all is well, and it shows up in a new browser window (IE8 or Chrome, in my case). In fact, if I have a string of DISPLAY DOCUMENT requests (up to 12), they are all fine on the first execution of my PROC that requests them. If I close the PDF display and then run another report or set of reports (DOCUMENTs), that outcome is also fine. However, if I leave the browser open (IE8-), and then run another report set, I often see one or more of the earlier reports again. When using Chrome, it does not reuse the window as I see with IE, so the problem is different - many many windows, which is equally annoying... I am convinced this is an issue related to the PDF work files generated in the ...\Aware folder and the call to Acrobat Reader (version X in this case) to show them. Somehow it gets mixed up and either is unable to overwrite the file and replace it with the new PDF, perhaps due to inadvertently keeping the file open when it should not, resulting in a display of the old one, or the software is confused and requests display of the wrong file, as it leaves a few of these around in the folder. I believe this is not that the actual generation of the DOCUMENT from the application is somehow done incorrectly. I never see this when the same routines request PRINT DOCUMENT instead... It has something to do with the routine that generates and displays the PDF.
If you see mistaken display of older documents, be aware that closing the browser window has for me resulted in a positive outcome every time.