X265 encoded video will only play on (some) AppleTVs if changed to ACC Stereo from 5.1

Plex Players Streaming Devices
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2

Where do you change the playback setting to ACC stereo? In the client or you re-encode the file? I don’t think there is a setting like this.

I have a similar issue on Apple TV HD, pre-4K:

I just assumed it can’t play HEVC.