Video cuts out intermittently after routing through Marantz AV amp

I’ve been using my Vero 4K happily for a long while but recently upgraded my AV amp to a Marantz unit, so my HDMI output from the Vero 4K now goes to that rather than directly to the TV.
I’m having issues with the video dropping out every few minutes or so. The audio seems unaffected. The video dropouts are intermittent and not in the same place every time. The audio doesn’t drop out, just the video. When the video cuts out, it’s always for the same length of time (around 3 seconds or so) and the TV shows an on-screen display “HDMI1” implying the input has changed or been reset - the same thing you’d get if the cable was unplugged and reconnected. I’ve changed the cable, no effect. Interestly, in the process of gathering the logs I played back the same video file after a reboot (with debug logging switched on this time) and the video seemed to play fine. I’m playing from a Windows 2012 server via SMB (FStab mounts) via a cabled connection. Movies don’t seem to be affected in quite the same way that TV shows are.
This didn’t happen with a direct HDMI connection to the TV, only since the Marantz AV amp was installed into the HDMI chain.
Anyway, here’s the logs:

Any help appreciated, thanks.

Try another hdmi cable

I already have, but only swapped with another I had.
I’ll get a brand new one and see what happens.
Nothing in the logs jump out at you?

There’s a couple of OnLostDisplay events which is odd.
Does enabling HPD lock and rebooting help?


What model Marantz is it?