PVP level 0 is not a updatable level in the game HUD.
Log out with PVP level 0 shown on HUD.
Log back on and the PVP level on the HUD shows 3 (in green circle)
Enter a building - HUD PVP level 3 disappears (green circle empty - no number).
Exit back to NU - HUD PVP level still empty.
Not tested: approach NU exit to observe HUD PVP level switch from empty to 1.
(Fairly sure that is what will happen)
