Default [Q] Lockscreen Problems

Dear all,

a few days ago I started using Cyanogenmod 10

In Settings lockscreen is enabled with cLock-Widget, till now I tried normal unlock (move only), pattern, PIN and Password but in 90% of all cases, if I switch of my Xperia with Power, it is NOT locked. Pressing Power again, after a few seconds, minutes or just hours still show homescreen order latest app which was open. Same if I do not use Power but waiting for automatic Lockscreen.

Do anyone has the same problem or just know how to fix that?