What does the now-playing screen for the Beam show as the input and format when it goes silent?

pretty much nothing

That looks like the TV is not sending anything to the Beam. The usual advice (I'm not good with TV settings) is to update the TV and Sonos to the latest, then power both down together and then back up.

You might search here to see if others have posted about your TV and a solution.

I’d agree with ​@Stanley_4 , it sure looks like Sonos isn’t receiving anything at that moment. Beyond his suggestion, which is a good one, I’d also recommend checking the seating of the HDMI cable between your Beam and your TV, to ensure they’re connected properly. I’d also suggest, if that doesn’t help, that you submit a system diagnostic within 10 minutes of experiencing this problem, and call Sonos Support to discuss it. Don’t post the resulting diagnostic number here, they get sensitive about GDPR.

There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution.

When you speak directly to the Support staff, they have tools at their disposal that will allow them to give you advice specific to your network and Sonos system.

I've tried all of the usual steps, updating both the controller/device and my TV. I suspect it's an issue with hdmi delay. If I turn on my TV it takes a few seconds of scrolling through my menu until I hear sound coming out of the Beam. It's connected via HDMI eArc in the 3rd HDMI input. I'll run a diagnostics and see. Or maybe it would be better to switch to optical if the issue persists

There’s certainly a delay between when I start playback of Hulu on my Apple TV, before it begins to feed my TV set to provide to Sonos. It usually only happens at the first time I initialize the Hulu app, I don’t experience this when changing ‘channels’ from within. But I’ve always considered this a function of the data not being sent (yet) to Sonos, not a failure of Sonos to process data sent to it. 

However, my previous advice stands. Contact Sonos. They’ll be able to understand if there is an issue in their processing of data, or a complete lack of data for their device to interpret. No matter what my experiences are, hard data will always overcome that.