Firefox V65
Xubuntu 18.10
Very recently Firefox (V64 and nor V65) have started making a "Pewwwww" sound when a new page loads in a new tab. Not all pages, but a lot of them. Here are just a couple of examples:
https://dailycaller.com/2019/02/13/cory-booker-go-vegan-meat-not-sustainable/
https://www.arcamax.com/thefunnies/dilbert/
As I said, this happen when I open the link in a new tab, but doesn't make the sound again when I reload the page content in the already opened tab. This also doesn't happen in Chrome or Opera on the same OS.
This is very annoying. Does anyone know why this occurs and how to stop it.
Thanks.