I've reported this a few times via "Report a Problem" on the Xbox but thought I'd see if anyone else is having audio issues with the Beam app. Seems to only be streams that are using FTL (non-FTL steams seem fine). I also get audio through optical out on the streams since my headset uses optical, but I get no audio via HDMI though my Denon AV receiver for the FTL streams.
Anyone else having issues?