The blank sessions that you see in Pulse Live Monitor are due to CAM Security.
If you open two Architect windows and try to login to the same instance with security mode 1, you will see that TM1 is going to create 2 sessions:
However with CAM Security the first time you log in to Architect, TM1 will create one session with the username but if you log in a second time with the same user, TM1 is going to create a blank session:
If you check on TM1top you will see the same sessions:
I’m not sure about the explanation but it might be linked to how the REST API handles the sessions and threads: