If you try too simple a password with mysqladmin, you get the wrong error message:

[root@mg-m103 ~]# mysqladmin password -p
Enter password:
New password:
Confirm new password:
[root@mg-m103 ~]#

[root@mg-m103 ~]# mysql -Ap <<< "INSTALL SONAME 'simple_password_check'"
Enter password:
[root@mg-m103 ~]# mysqladmin password -p
Enter password:
New password:
Confirm new password:
mysqladmin:
You cannot use 'password' command as mysqld runs
with grant tables disabled (was started with --skip-grant-tables).
Use: "mysqladmin flush-privileges password '*'" instead

The server sends the correct message:

recvfrom(3, "w\0\0\1\377\n\5#HY000The MariaDB server is running with the --strict-password-validation option so it cannot execute this statement", 16384, MSG_DONTWAIT, NULL, NULL) = 123