Yes, my experience with the 2 user Zulu license is that all extensions get a 90XXX extension built. If no Zulu user logged in for that extension, then it shows as offline extension in your Dashboard graph and in Reports->Asterisk Info, chan_sip or chan_pjsip.
I have tried disabling Zulu for each user that is and will not be using Zulu in User Management. Even with an “fwconsole restart” from the CLI, it does not change that fact that they appear in the above mentioned places. I have even follow advice from another post about using Delete them from under: http://your.pbx.ip/admin/config.php?display=devices found in post Getting rid of 90xxx extensions to no avail.