Hi,
This happens because mysql.sock is additionally defined in /etc/mysql/conf.d/settings.cnf file and entries are like that:
socket = /var/lib/mysql/mysql.sock
pid-file = /var/lib/mysql/mysql.pid
As you can see the path is different than default one which is defined in my.cnf
[client]
port = 3306
socket = /var/run/mysqld/mysqld.sock
You can comment mysql.sock line in /etc/mysql/conf.d/settings.cnf file and restart mysql or override it in .my.cnf setting correct path.
I hope this will help you for solving the problem until it gets fixed globally.
Regards,
Ali Nebi