I am having a similar problem, where after about 2 mins or so the DVSwitch mobile app running on an Android mobile device just hangs up on all modes, Eg NXDN, P25, YSF etc, whilst connected on a cellular connection, when a push the "Register" button I get USRP :REG OK notification again, and the connection continues for about another 2 minutes or so, unless I am in a QSO where the app does not hang up.
If I run the same android device and app on my home wifi connection I don't get disconnected. I've also tried connecting using another phone's wifi hotspot on a cellular connection and get the same result . The equipment I am using is a RPi 3b only running DVSwitch2 with updated scripts and binaries connected thru my homes 5G wifi connection to my router the 1 away to a stable 90Gbs cable connection.
However, on IAX2 connection to an Allstar node I remain connected.