STRANGE- TWIGHLT ZONE PHENOMENON. Can anyone explain?

Storms create ionized energy as that is what lightning is. Dad was a nuclear physicists  and also taught astronomy.  Yes cables can act as antennas and shielding helps,out comes the aluminum  foil. Call the manufacture. Nothing electrical should be plugged in during a storm. Some articles state braided copper ,aluminum foil ptfe and air best insulators. Enjoy the science.

You may also creating ground loops if not all plugged into same outlet circuit. 

@OP Ionized air (during storm activity) increases RF sensitivity. You Entreq box and cable are acting as an antenna and allowing you to pick up some RF transmission.

If you blind a/b test that box connected and disconnected, I'd be interested in whether you hear any difference at all.

That is when there is no storm activity.

Also, try shaking the box - seriously.

Clearly there are some mysterious and borderline dangerous mystical issues with possibly haunted gear. The only viable solution is to pile up all your gear someplace and set it fire, making sure the replacement gear is blessed by some sort of holy man.

Based on your latest experiment removing the wire on the Entreq end, the box is acting as an antenna under the right conditions. To me, this means that under non-storm conditions it is probably doing the same but is inaudible, and potentially sending noise into your component. I am intrigued by grounding boxes, but I would say this one has some issues and I would pull it.

As an aside, I have been trying out some Ethernet switches and various Ethernet cables, some with shields tied at both ends, some floating, some with plastic jacks. Both switches I have tried have chassis grounding points. One thing I have learned is you don’t want any difference in ground potential between your components/grounds as it can result in noise on your system ground as it tries to balance. I am not an electrical whiz, so someone with more knowledge feel free to correct me, I am just speaking from experience.