I purchased the devices in May 2020 and have started having sound issues. I have multiple Roku devices and only having issues with this model. The only temporary solution I have is unplugging the device from the power source and then plugging it back in. I guess it's safe to say a hard reset is required. Which should not be required on a new device. Requesting a permanent solution for the devices from Roku.
I have the same problem. It was intermittent at first. Now every time I turn on my TV I have to reset the Roku device because there’s no sound, it happens every day. I tried unplugging the device and plugging it back in, doing the system restart through the app, I tried using a new HDMI cable, nothing works it loses sound every day. Hoping there’s a software update that fixes this issue.