We have noticed that our DEV and TEST instances the plugin was force installed when we upgraded.
This caused 2 ACL's to be created that limits the sys_user table from being read unless your users have the role sn_walkup.walkup_login
Basically Any field that references the user table was blocked from the forms - ie ITIL couldnt see assigned_to field.
Disable the following ACL's or give ITIL the role above.
ACL - sys_user.name - b08b3bdf93b0f61076eaf686dd03d63b
ACL - sys_user - 6b6c3f1393f0f61076eaf686dd03d629
They have opened PRB1955938 - Move Walk-up Experience ACLs controlling global fields into if folder on AWA
