AR12 USB Bluetooth automute?

Hi. I'm about to buy this mixer, and have 2 days to try it out. Unfortunately there is a problem with the Bluetooth chael. All the songs om my iPad has 1 second silence and 4 clicks on the drum before the music starts. But sometimes the music has started before you can hear anything, sometimes I get 2 or 3 clics before the music begins. Is there a kind of mute that has to open before you can hear anything? I tried to coect my old Bluetooth-receiver to one of the chaels, and had no problems. Can you help me? Regards Torben