PollNotifications continue to be requested when the user is not connected

[Jogo27]

The issue appeared on my portable on revision d259d34. This can be seen in logs like

2021/06/09 16:25:33 127.0.0.1:55398 /a/pollnotif 403 Unauthorized: Unlogged user

In the browser, the title bar indicates that the user is not logged anymore:

This raise two questions:

1. Why are the notifications still requested if the browser has detected the deconnection?
2. How is it possible to be deconnected while the page is displayed?

[Jogo27]

I had two tabs with Itero opened. May be an explanation for the second question.

[Jogo27]

The issue seems to appear also with the following scenario:

1. Log as a user with notifications on.
2. Log off.
3. Log as a user with notifications off.