I'm using the last Kubuntu 14.10, with spotify 0.9.11.27.
The client will randomly freeze any interaction with all apps. The mouse pointer still available, but I can't click anymore. The KDE app launcher is frozen too, and the rendered desktop looks strange. I think, the KDE plasma desktop is entirely frozen.
The only thing I can do is ALT+F5 to switch in Console mode. I use it to restart the computer.
I saw some subjects here, about SPOTIFY hijacking mouse clics, but I'm not sure it's the same issue.