Facebook Messenger no longer has the blue dot on the tab when a new message comes in

I’ve always got Messenger open in a pinned tab, as it’s my primary way of communicating with friends…

Recently it stopped showing the blue dot when a new message comes in, so I miss out on friends texting me… I don’t know if it’s a Firefox related bug, but reloading messenger doesn’t seem to work.

116.0.3 (64-bit), w10.