Vero 4K HDMI CEC stopped working

Starting today, I am no longer able to control one of my VERO 4K boxes using the TV remote. The following appears when it boots.

Swapping the 2 boxes I have, it is always the one on the main TV that does it.
I can think of nothing that has changed since last night.

Disconnect all devices in the chain from power (not simply standby.)

Wait 5 min and re-power everything again.

Report back if issue persists.

That seems to have fixed it for now. Will check again later.

Many thanks.