Compiz keybindings change on reboot

I have a problem with Compiz keybindings on Ubuntu 13.04 (but it also existed on 12.10). I run a multimonitor setup and use the Put plugin to move windows from monitor to monitor with the "Put to next output"-function.

I have bound Ctrl+Alt+Keypad Comma to move the windows. When it works, the shortcut-button in CCSM says <Primary><Alt>KPSeparator.

However, after rebooting, the key is changed to <Control><Alt>KPSeparator. The effect is that windows move as soon as I press Ctrl+Alt, but before I press Comma. Since I have many other keybindings relying on Ctrl+Alt, I very often accidentally move the window because I wanted to press another shortcut. I can fix the behavior manually by entering CCSM, removing and recreating the keyboard shortcut. This problem does not occur for any other Ctrl+Alt based shortcuts (for example in the Grid plugin).

There's a couple of screenshots here: http://askubuntu.com/questions/295627/compiz-keybindings-change-on-reboot