I haven't seen a report on this yet, so I'll start the post here. There's a thread on the CW subsection where multiple people have voiced that they are seeing it as well(
http://nw-forum.perfectworld.com/showthread.php?458751-Icy-Rays-Broken).
The first part of the bug is that the second spell cast that actually casts the rays doesn't execute reliably. Often times when you mash the key, your character waves its hands a couple of times as if trying to cast it, but it takes several attempts for it to actually execute. The first cast which marks a target works fine.
The second part of the issues is that once the spell finishes, the icon in the power slot doesn't show that it's on CD. You have to press the key again in order for the CD timer to show up.
Both of these combined means that we have to constantly mash the Icy Rays key in order to actually cast the spell and know when it's ready again. This is pretty annoying especially when you're trying to time your spells. A prompt fix would be appreciated.