Droid won't always lock

[Chillout]

Hi all, question that I have yet to figure out and have so far chalked up to a quirky issue with with an app or just my dumb luck.

I run the stock 2.0.1 setup, I have the screen timeout set for 30 seconds on my phone. Basically when I wake my phone up whether it's after 30 seconds or even hours after not using it, the screen is not always locked. Sometimes it is, sometimes it is not.

Obviously if I set the location/security option to require a pattern it will always lock when the screen times out but if I don't use that, the stock slide to unlock screen is not always engaged when waking up the phone. I would prefer it to lock with the stock slide lock atleast when the phone is not in active use.

Is this due to some app that perhaps is causing it or just a known issue or? I do use bettercut and Apps organizer to keep my stuff in order but other than that it's just your basic everyday apps..nothing specific related to screen lock and what not.

Any ideas?

Thanks!!!