It's a known bug, and looks fixed in 2.5. There's also a number of lpsched patches out for Solaris: 101025-xx (2.2), 101317-xx (2.3), 101959-xx (2.4) and 101960-xx (2.4/x86). Make sure you install those.
Regardless of what other patches you apply, if you have a printer connected to your system running Solaris 2.4 or later, and if that printer uses NeWSprint software, you must apply patch 102113-xx. This patch is included on the Solaris CD in 2.4 and later releases. This patch is also required if you are running Solaris 2.3 with kernel jumbo patch 101318-55 or later. Note that this is a NeWSprint patch, not a Solaris patch, and hence it will never be integrated into any Solaris release.
"lpstat" on the clients on a regular basis, for some reason this clears the old files from the queue directories.