Here's a strange one. I have a CS1K running 5.0 and starting yesterday all of the M3904 phones started acting up. When you hang them up, they no longer return to the idle display screen. The call timer still goes, and what ever display tree you were on remains until you hit the goodbye key. When you hit the goodbye key, it returns to the idle screen. Other than that, the phones work normally. Has anyone run across this?