This is fixed.

Once I understood what happened, the fix was actually easy.

Assumed scenario:

You do a login from a browser
You work in the interface
After a while, you do a login from another browser or from another device
That overwrites your current session and the later one becomes active
Thus, the previous session becomes inactive
The background worker process on the first session will discover that the login is no longer active
It will redirect you to a login page
You do the login
You had a blank page (now, you should get the reload of the interface)