User-friendly Aliases for OpenLDAP
When using Open LDAP to authenticate users, it is recommended to assign users a simple Alias.
The Alias field is composed of the user name and domain name if the option Use authentication server is enabled. This is because of how the system authenticates against the domain.

To log in, full login information is required - but it would be inconvenient to have it in the user's Full name as this would make logging into the web interface more difficult, and also mean this string is displayed rather than the user name once they have logged in. So, the system uses the Alias field to store this information.
Configure User-friendly Aliases
To enable users to use a simpler Alias, the options are:
Disable the Use authentication server if it is not required.
Use or create a unique attribute in LDAP for a user-friendly Alias, as shown here:

Users will have the alias generated by the system so they can authenticate against LDAP, another alias that will allow a more user-friendly login.
Furthermore, it is possible to export a CSV file from the data synchronized with LDAP, modify it with scripts or automation tools/macros to add additional aliases, and then import this CSV file to update the users (schedule the run of this CSV update after the initial import of users from Open LDAP).