For those who are using a DAC and still having this issue, make sure you have any DAC input monitoring disabled. I’m using a Focusrite Scarlett and when I had toggled of “Direct Monitoring” which I had accidentally left on, the issue went away.
It’s interesting that UE seemed to be the only application I’ve tested that affected this, and that disabling real time preview reduced the noise, but my best guess is that the cable or amp that I left plugged into the DAC was picking up the interference despite being turned off.