LG C3 OTA Channel Sound only with PCM, Tablo Gen4

I have a very peculiar issue with major network (e.g., CBS, ABC, Fox, NBC, CW) channels and my Gen 4 Tablo. The only way to get sound from the Tablo is to put audio out on the LG to PCM. Here’s what’s peculiar.

Other channels’ sound works fine when the LG audio out is set to Auto. For example, the local ABC affiliate is channel 5.1. Channel 5.3 is METV. I get no sound on channel 5.1; the channel 5.3 sound works fine.

Here’s my complete setup: LG C3, FireTV Cube (3rd Gen), Bose Soundbar 600, Tablo Gen 4. All devices are current on firmware. I’ve seen the Tablo Gen 4 did have issues with certain FireTV devices but a fix for that was released in Sept, 2023 by Tablo.

Here’s the other weird thing. I also have an older Vizio (M50) connected to a FireTV Cube Gen 2 and a Bose Soundbar 500. All OTA channel audio works fine.

Anyone have ideas on how to solve this given my specific hardware?

You can try disabling “surround sound passthrough” in Tablo settings to see if that helps. I remember reading some were having issues when they added that feature.

Brilliant! Turns out surround sound was disabled. Once enabled, everything works as expected. Thanks for the help!!