I can’t see what it could be in the HTC Connect software as there is NOTHING being changed on the phone at all. Even if both Shairtunes and Shairport use the same core, there has to be some kind of buffer setting or similar causing this. It’s not the Pi as I’ve tried the Pi, NAS and Windows machine as the LMS server and the Pi and Windows machine as receivers.
I’ve played with the buffer settings in Shairport options but are there some other options somewhere? Perhaps hidden from normal view?