Apple tv 4k generates very loud distortion

Just bought an Apple tv 4k so i could enjoy dolby atmos via netflix. The atv is connected via a premium certified hdmi cable to my NAD t777 receiver.

After 20 to 40 minutes into almost any show on netflix a very loud pop/spike is played, it’s really ear piercing loud. Then the sound gets all distorted. Switching to another hdmi input and back again to the atv input on my receiver restores the sound back to normal. My master volume level on the receiver is set to around -28db so way of the maximum level. The spike is loud enough to scare my cat, luckily my speakers weren’t damaged (yet). To be on the safe side i enabled the receiver’s soft clipping feature.

Never had this issue in 5 years i used apple tv3, although that was connected directly to my tv and used optical out from tv to my previous harman kardon avr65 receiver as it didn’t have hdmi.

The NAD receivers can be finicky but i didn’t find any reports resembling this issue. Turning my attention to the apple tv returned endless google hits, even going back to the atv2.

Switching to another playback device is no option. In the future I’d like to upgrade my philips 21:9 tv to a panasonic oled that also has atmos support in the built in netflix app but for now the atv 4k is it.

How can i prevent this sound distortion?