A detached screen cannot be attached and eats 100% CPU. The only thing that seems to tame it is a kill (TERM or KILL). I haven't checked this with other kernels than the stock RedHat 7.0 SMP kernel or any other version of screen than the supplied one (screen-3.9.5-13).
Can you try this with the current rawhide screen?
Rawhide screen-3.9.8-3 works. A detached screen can be re-attached, and doesn't eat 100% CPU. It seems that the bug is fixed.
cool