Running Skydemon version 3.16.9 on a Samsung SM-T713, Lineage Operating System, Android 10, PilotAware Rosetta

On Wednesday evening whilst flying I did not have any audio traffic alerts though the relevant aircraft were visible both on Skydemon and the radar screen on the tablet and also on a separate phone used purely as a PAW radar screen. Two of the other aircraft were close enough to be  red on PAW and well within the parameters I've set for alerts. I use a cable from the tablet to the headset control box and have had the same set up for 2 years without any performance issue. None of the settings have been changed on the tablet or the Rosetta, all the connections are good and I'm getting all the usual Skydemon terrain, airspace alerts etc. The headset batteries are good and the ANR is working as it should.

So I'm a bit flummoxed as I cannot see any reason for the loss of audio.

Grateful for any help!