Quote Originally Posted by SeraviEdalborez View Post
X cannot be used is caused by some weird UI lag between you and the server or something. It most often shows up when you hit a lag spike or leave your game client open for a long time. You can tell it's in effect when Multishot's recast shows 0:12 or something after using it instead of 0:15. The icon will light up as normal but you will have to mentally autocorrect for the display discrepancy. It's annoying, but closing the game client (not just logging out, Quit at main menu too) can help reset the delay.

It's been an existing problem for quite some time now, not sure if the fault lies with the game or one's internet connection/PC specs.
You probably explained this best. I think this all comes down to the games sever/client issues, and it has little to do with our PC specs or internet connection. It's just something that causes problems to lots of game functions, not just this, and SE needs to fix it. But yes, the best thing you can do is just shut down the game completely.