Are you experiencing that weird sound on the iOS app of Facebook? Meta is aware of the problem and has recommended a quick remedy.
The said issue is about Facebook’s refresh ping sound annoyingly playing all the time even if you’re just scrolling normally through your feed.
To get rid of it, Meta suggests disabling in-app sounds on the Facebook app altogether. To do so, open the app and go to settings > tap Media under Preferences > under Sounds, disable In-app sound.

A representative from Meta claims that it is an “unfortunate technical error” and that they are currently in the process of fixing it. Make sure your Facebook app is updated everytime for when the fix comes out.
It appears to be a problem in select versions of Facebook on iOS. Meanwhile, no similar issue has been reported for the Android version.