Intermittent Noise - Suspected RF

[musicmanca]

Hello JS forum community! New member to this forum, going to try and follow all the rules! I originally posted this on GS in the studio build sub-forum, but didn't feel like anyone saw it.

My room description: a commercial facility designed and built to be studio. High-end gear and acoustics. It is worth noting that we are located in an industrial area. Hopefully this is a sufficient room description.

When I'm using a tube mic or a tube guitar amp I'm picking up intermittent noise (normalized & attached).

When using an EMF meter I pick up nothing suspicious. I've tested the space using a single coil pickup with a battery powered amp and get the same intermittent noises, so I'm lead to believe that it's RF interference.

I've bought a cheap RF blocker adapter and this has knocked the noise's volume down a decent amount, but it's still there. Tried Ferrite Clamps/Beads and they make little to no difference. I have a vintage Neumann 67 and oddly enough this tube mic is 100% solid, there's no intermittent noise, even having the gain and monitors fully up, it's clean.

So now I'm quite confused because it seems like I'm having an RF issue, but what throws me for a loop is how the 67 is unaffected.

At a stand still and looking for any information or things to try. Does this sound correct to anyone? I'm also having a difficult time coming up with the next step in problem solving if anyone has any opinions they might be able to share.

If there's more information I can add or any questions I can answer, please don't hesitate to ask!