How do I get Roon to stop and give up control reliably when playing live radio?

Using Roon remote on iPhone, how do I get Roon to stop and give up control reliably when playing live radio?

When I switch on my TV, it should change the input on my Linn Klimax from Roon to the correct HDMI input.

Sometimes Roon doesn’t give up control and I get no TV audio. This happens in particular when playing live radio and the queue is empty.

Roon does not relinquish control to Linn, even when powering off.