Recently the Notifications box (which drops down when you click the bell in the top right) has changed design and no longer shows me any notifications. Even when I know I should have notifications, the box is empty.
However, when I switch to one of my other accounts, I get notifications in the box as expected (still with new design):
If I go to Google+, the notification box uses the previous design and properly shows my notifications:
If I open YouTube in Chrome, it shows me the previous design and properly shows my notifications.
In summary, when I'm on YouTube in Firefox with this specific account, my notifications do not show. If it's browser specific, why is it working when I switch to another account? If it's account specific, why is it working with the same account on Chrome?