My carrier is Verizon.

Kernel version is 4.14.113 updated on May 10th, 2021.

And ever since then I've been hearing a strange (double?) bloop sound from my phone usually shortly after connecting to the internet. (I do not stay connected, I turn off data / wifi if I have no reason to access the internet.)

The bloop is not accompanied by any text notifications or popups, it just happens.

I tried to use the Notification History to see where it was coming from, but nothing. Except with the history tracking on, the phone had a conniption fit when a message came through, ...

Any suggestions on what it might be?

 

So I connected an audio cable to my phone and recorded the sound.

 

Nothing like that, that is just from turning on the wifi or mobile data, very shortly after I do that, bloop. Don't have to be doing anything with it, to record that bloop, I just connected the headphone out to my computer, turned on the wifi, and walked away for about 10 minutes.