I have also tried this (Typing !song command [Nothing], Opening iTunes and playing song [Gives correct song title], Stopping song [Gives Song Title] and closing iTunes [!song again produces nothing]). Each of these actions did not cause a freeze. This also does not make iTunes the active window (Placing it in front of everything) but I do know it used to do this.
Are you using the latest version of Deepbot? (v.0.4.7.2) ?