I can confirm that this problem is unique and occurring with Mac OS X 10.6.5 and the HP Drivers 2.5.2 for HP LaserJet and DesignJet printers. Most likely, the problem is with the Mac OS X 10.6.5 update rather than the HP Drivers 2.5.2 because:
(1) The HP Drivers 2.5.2 update has been out for a week, and was working just fine with Mac OS X 10.6.4.
(2) Some are reporting problems with printers from a different brand (like Epson).
(3) Mac OS X 10.6.5 includes CUPS 1.4.5 (10.6.4 included 1.4.4). This is most likely a CUPS bug.
You can report this bug in two places:
(1) At the Apple Bug Reporter:
http://developer.apple.com/bugreporter
(2) At the CUPS site directly:
http://www.cups.org/roadmap.php, then click "Submit Bug or Feature Request." CUPS (Common UNIX Printing System) is the open-source printing engine that Apple uses for Mac OS X. Many Linux and other UNIX systems also use it. In 2007, Apple assumed control of the CUPS project, although it remains open-source and free-software (GPL).