Lockups after unlocking screensaver

Since installing RC2 I have twice experienced "lockups" upon unlocking the screen. I have never experienced these before. Once "locked up" the mouse has no effect and there is almost no keyboard effect. However numlock and capslock keys still flip their indicator LEDs and ctrl-alt-Fn can be used to switch to another console. First time: as root I restarted tdm-trinity. I didn't notice if there were any error messages. When Trinity restarted it was on a new console - alt-F8 instead of alt-F7. The second time: as root I stopped tdm-trinity. I noticed error messages saying the stop had failed. I killed -9 kdesktop_lock, stopped tdm-trinity again, and started it. This time Trinity started on the expected console. I'd appreciate any suggestions of any additional steps I should take to help diagnose the problem if it happens again. --Mike