We use the headphones to monitor sound in the Mixer, and all the channels that we want to hear in headphones are selected with the "SOLO" button on. We also use the StudioLive Remote app on the iPad and when we make a change in volume on one of the channels on the iPad, the sound is cutoff in the headphones coming out of the mixer. We have to press on and off on any of the "SOLO" buttons on the Mixer to get all the headphones sound back. Basically, seems like when a change is made on the StudioLive app on the iPad, it wants to store that change back in the Mixer, but when it does that, it mutes the SOLO sound coming out in the Headphones until you press the "SOLO" button on any of the channels on the the Mixer.
Mixer we have: STUDIOLIVE 32.4.2AI
iPad software: Studio Live Remote app.