Have had sky HDI Boxes forever. Recently purchased new 4K Samsung TV and a new 4K Denon Amp about 6 weeks ago.   Using an Intel NUC to feed things like netflix and disney+ through the amp to the TV.   Everything connected via HDMI and a 3 to 1 setup in the living room with a left and right speaker, 1 centre and 1 sub. 

Noticed on netflix ( watching through the Intel NUC) when i hovered over a new show and there had previously been no sound - static crack as the sound started. After digging through numerous forums and trying various power saving settings ( I didn't appear to be the only person with NUC and sound issues )  i found a post saying to change the 5.1 output from the NUC to stereo - all good. Fixed that. 

For last few weeks when watching SKY - live and pre-recorded shows - no issues when they are playing.  Use the FF or RW to skip through ads and when you press play to resume - ' crack ' through the left speaker.   This only appears to be happening on the main terrestrial TV channels - 1 and 3. We don't have an aerial connected so watch the free to air via the skybox.   Just been watching sky sports and FF through a couple of rugby games - no issues. I can only replicate it to date on programmes that are watched on TV 1 and TV3 via the skybox. 

I'm guessing it's either the skybox and how the sound is carried on a few digital channels or something with the Denon amp.  Have checked all the wiring etc... Now at a bit of a loss as to what to try next.

Generally it all works but the sky thing is a constant issue now so any pointers or things to check appreciated.

Thanks in advance

Ged