Audio issues when viewing 4K channels

[Buckala]

I have a very odd issue with audio when viewing 4k channels. I noticed when viewing channels with my new wireless 4k Telus TV OPTIK box , the audio goes MUTE but will come back on when I change to an HD channel. I am referring to the the audio from the internal speakers of the TV. The strange thing is that if I power up my Denon AVR 4400 receiver the audio is functional for all stations including the 4K . For those who are wondering why not use the Denon at all times is because this is the TV in our master bedroom and at times I do not want the Denon in 5.1 audio mode late night. So I performed a few trouble shooting measures to see if the same would occur if I connect the 4K box HDMI directly to the the 4K TV. The same issues occur.... no audio on the  internal TV speakers when viewing 4K channels with audio viewing HD channels and when I reconnect the HDMI back to my Denon receiver...voila..... DOLBY DIGITAL Plus audio emanating through out the room. I am using a 4K 55" LG TV and for the life of me I cannot find any input setting to fix this issue. In all instances I do get video for both HD and 4K channels. Any ideas out there in the TELUS OPTIK TV world? 

[A-B]

Hello. If the problem persists, we can definitely investigate this further for you. I'll send you a private message to discuss.

[A-B]

Hello. Just following up again as I've received some info from our Optik team, including some possible workarounds/troubleshooting. Here's a list of things you can try to see if they help:

- Update your screen resolution (720/1080); it can be then be swapped back afterwards.

- Update your aspect ratio to standard definition; it can then be swapped back afterwards.

- Check and/or reseat your HDMI cables to test.

- Try a different port on the TV itself (if available).

- Try rebooting your box while your TV is on.

- Try turning on the HDMI CEC setting (Settings --> General --> HDMI CEC settings --> Enable). Save and reboot.

- Try a sequential reboot of your STB/PVR (unplug power cord from your modem/router, then unplug power cord from your TV equipment, wait 15 seconds, and then reverse the order by plugging the TV equipment power cords back in, and then finally the modem/router).

- Try a new HDMI cable if you have one, or try an optic cable (some Denon receivers need an optic cable to work). 

[Ds3]

I have a similar problem. No sound over tv speakers.  A new problem as has worked before. All other channels work. Sound occurs for about one second as you change channels.  Do the 4k channels have different sound settings. 
thanks

[Ds3]

Solved by going from Dolby to Stereo. Works for both