In 6.2 you can press a key when you see the screen starting fading for an impending screenlock. With the beta packages (1.10.6-1.el6.i686) this doesn't work, and you are left watching a quite slow fade until you are brought to a screensaver unlock screen. The cause might be the fix for rhbz#748704
I can remember that I saw this behavior as well, but not any more right now. Just FYI.
Simo tested a patch for me, and it appears to have worked. Writing this down so I don't forget: This is indeed caused by: * Mon Mar 19 2012 Adam Jackson <ajax> 1.10.4-14 - xserver-1.10.4-sync-revert.patch: Revert an edge-case change in IDLETIME that appears to be more wrong than right. (#748704) That patch reverts two hunks from Xext/sync.c. Those hunks would be correct, if they swapped places. I don't believe this bug to be a blocker, inability to interrupt the screensaver is merely cosmetic.
Upstream fix for this was: commit 4a6f42dda00ba3b5616f8a86f0d4c9a652c7d9d4 Author: Adam Jackson <ajax> Date: Mon Jul 23 16:34:28 2012 -0400 sync: Fix logic error from b55bf248581dc66321b24b29f199f6dc8d02db1b This change is included in xserver 1.13.0, current RHEL6.4 build is xorg-x11-server-1.13.0-1.el6. MODIFIED
*** Bug 848016 has been marked as a duplicate of this bug. ***
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. http://rhn.redhat.com/errata/RHBA-2013-0299.html