DebianEdu: cannot set password for users

DebianEdu bookworm

1. add a new user as teacher
2. try to set password for the new user
3. Warnings:
Deprecated: substr(): Passing null parameter #1 ($string) of type
string is deprecated in
/usr/share/gosa/plugins/admin/users/class_userManagement.inc on line
352
Deprecated: Function uft8_decode() is deprecated in
/usr/share/gosa/include/password_methods/class_password-methods.inc on
line 391
4. try to login using the password
5. password is not correct, login fails.