Phantom noise popping out randomly in mic

Hi everyone! I have an issue with my mic and audacity which I cannot fix.

Every now and then this noise appears even if the mic is muted or switched off. Sometimes it disappears, I can record wonderfully for a couple of days and then it pops out again.

It really get my noise floor CRAZY and, funny thing, you can see it just on spectre, on 5k line.

Audacity: 3.0.2, but it was doing it also on the previous version;
Mic: Røde NT1-A with shockmount, pop filter and røde boomer
Mixer: behringer xenyx QX1204USB;
System: Windows 10 on PC

Someone had this issue? I’m literally getting crazy.

Post the sound here, all 7 seconds of it as shown in your picture.
(Wav mono, 44.1KHz, about 1.2MB size limit I think).
Others will analyze it and try and figure it out.

It seems odd that there is about 3.2 secs of just blank “carrier”, followed by about the
same period with what looks like data on it.

Are you perhaps in Europe or a country/region where mains signaling or remote meter reading is used?