Upgrade from 10.5.8 to 10.5.12 overwrites configuration

After upgrading from 10.5.8 on my galera cluster the configuration files /etc/mysql/mariadb.conf.d/50-server.cnf and /etc/mysql/mariadb.conf.d/60-galera.cnf were replaced by the default files from the packages retrieved from an official MariaDB repo mirror. As a result of this the node starts with defaults and the cluster functionality is disabled. Thus the node does not connect ot the cluster again.