Curiously does this issue occur on the demo disc that was originally supplied with the system? Have you tried to unplug your system from power for a full minute, then plug it back in? Also, there are some rare occasions where electronic products around the system will cause this issue. Can you move the Wave SoundTouch into a different room to test?
If the above still does not resolve the issue, I would recommend contacting your local support center. If you go to our global page HERE, you can select your country, then scroll down to the bottom of the page and click "Contact Us". This should provide you with the phone number, email, and chat services for your country.