The problem seems to occur only on Intel-based Macs. The primary glitch apparent after updating to Mac OS X 10.4.8 with regard to Illustrator is an inability to properly use the application's 'pathfinder' tool, which is used for manipulating compound shapes. One of the most popular applications significantly hampered by the update to Mac OS X 10.4.8 is Adobe Illustrator. Fortunately, there are often temporary workarounds, or kludgy hacks that can make the situation bearable until patches are released. Updates from developers are often required, taking the problem solving process out of users' hands.
Individual applications adversely affected by incremental Mac OS X updates can present some of the most challenging troubleshooting conundrums.