Lookup table used:
(The lookup table is referenced in object template for my extension attribute "extension/empStatus" aka Employee Status.)
When I try to set a value for this attribute, which is outside lookup table, it cannot be saved ("The value of 'Employee Status' is not a valid String.") - this is OK.
But when I have user with already invalid value in extension/empStatus attribute, such user cannot be saved or even the user editor does not allow to switch to other tabs because "The value of 'Employee Status' is not a valid String".
I consider this as a regression as our lookup table implementation was "tolerate existing values on load, but don't allow to save them" and there is no change to that attribute done in GUI.