Whenever I have heard the low volume beep I have made circles, walking. To try and detect it. The first initial beep can't even be replicated, though I did not test this to much. I have dug up treasures everywhere and know how it works. This that I report is not it. There is nothing in the plains that trigger the wishbone. The plains beep that i refer to triggered next to a small stone ruin far from any other biome.

I think there is a bug in the detection where it is constantly seeking and sometimes let loose one beep, albeit almost silent.

With how ship-wreck treasure is no longer detected and how it behave with the mountain burial tombs it seem like a bleeding item, maybe patch it up before it create permanent stains.

I would move this topic to bug section if I could.