guenterp62's post in iPad reconnect delay after screen unlock was marked as the answer
With a stable wifi connection, the app will stay connected during ipad-lock or even do a quick reconnect, if so configured.
The issue I have is in using the supported samsung usb-wifi stick in parallel with two line6 wireless microphones (XD V 55).
In this setup the ipad loses its wifi connection very often. Maybe the samsung signal is to weak or interferes with the mics.