I can hear it as well.

It starts roughly between 1:26 and 1:27 in this video of the fight: https://youtu.be/OqtPbLygc-A?si=QBSanbPEOyMyNdyA&t=85

Perhaps the audio team didn't check the spectrum visualizer for this noise?
I hope this gets fixed quick, as my friend can't focus when they hear it...