I haven't seen it mentioned, but Corel posted it on Facebook yesterday. Oddly the check for updates does not see the hot fix and tell you the older version is the latest. It can be downloaded directly from the Corel site here.
Here are the notes
Corel Painter 12 – Mac 10.7 Hot Fix 2 (English, Chinese Simplified, Chinese Traditional, Korean)
Hot Fix 2 updates the latest release of Corel® Painter™ 12 (126.96.36.1997) to Corel Painter 12 (188.8.131.520). This Hot fix addresses the following issues for users running on Mac OS® X Lion 10.
Selecting grouped layers no longer crashes the application
Painter no longer crashes when paired with a Wacom® Cintiq® Tablet
General refresh issues in Libraries have been addressed
General instability issues on Mac OS X Lion 10.7 have been addressed