We have a problem with logging in users from Active Directory. The usernames with the format "Domain\username" cause a cache problem (we create eZ users on the first successful login):

Cache key "ez-user-Domain\username-by-login" contains reserved characters {}()/@:

In the kernel the eZ\Publish\Core\Persistence\Cache\UserHandler.php replaces only the "@" character to "§", and backslash causes problems.
The kernel version is 7.4.2

Link to UserHandler: https://github.com/ezsystems/ezpublish-kernel/commits/master/eZ/Publish/Core/Persistence/Cache/UserHandler.php

We use fr3d/ldap-bundle (v3.0.2) for the LDAP functions.