As far as I can tell, the “issue” is that Mosaic Control operates in a stateless fashion; once its no longer the focused application on iOS, for example when the iDevice sleeps (or some other heavy application is used), Mosaic Control loses the DAC’s state information.
Once Mosaic Control comes back into focus, it re-issues an mDNS query and gets a dump of the DAC’s complete state. During that 1-2 seconds is when you see that “Lost Connection” screen (which in my opinion is a bit of a misnomer, it should just say “Please wait…”).
If your home network has more than a few extra hops between your WiFi Access Point and your dCS DAC, expect a couple of additional seconds of delay to the whole process.