I have the same with my 5K+, easy to miss until you get to a darker background, then very obvious.
I have only tested on one 1070 card at work so far. Tomorrow I will test on another card at home.
I will also make sure the cable is seated properly in the headset and other forum recommendations.
Is it cable shielding, environment noise? Do we have a handle on the actual cause yet? It seems a little common but not massively widespread.
I raised a ticket anyway so there is a record of it but hopefully I can resolved it so I am not without a headset again after waiting so long.