A friend was having interference problems with his MBP and it turned out one of his Thunderbolt 3 cables is not certified and although another is certified, it is on certified for 20 Mbps. Switching to a connector cable certified for 40 Mbps solved his interference problem. The TB 3 cable certified at 40 Mbps is significantly larger in diameter, stiffer, and more expensive but there is no interference when using it.
You might want to look at my musings earlier on the subject:
https://www.finetunedmac.com/forums/ubbthreads.php?ubb=showflat&Main=6113&Number=45905
