QN94A - Sound switches between HDMI and TV speakers

[IBol]

I bought a new QN94A recently.

I have a Sky  Q box connected via a Sky soundbar into the HDMI 3 eARC on the TV. It works fine but every 15 seconds it switched to TV speakers and back to HDMI which is very annoying. 

How can I stop this happening?

[Ginga_p]

Try sound settings. In there is a setting to change sound to different outputs and pcm ect