Help anyone else have problems with pattern unlock?

[mobile363]

I notice if i go to unlock the phone after its been sitting a while, it doesn't let me put the pattern in. It lets me touch the screen and all, but i draw 1, 2 or 3 dots or whatever and the pattern suddenly turns red. Its hard to explain. But my wife and I both have GS2 and both have this problem. Only after we both went to 2.3.5 via odin

 

[cuezed]

I also have this problem. Only happens rarely. Probably once every fortnight.

 

[thisnameistaken]

Yeah mine sometimes fails to track my dragging finger when it has just woken up, unless I go slowly.

Bit annoying actually.