mysqldump generating inconsistent dumps
The --apply-slave-statements parameter doesn't make sense here, as it is used when you dump from a slave, not from a master. 

And this one most likely causes your problems: --databases my-db

My guess is, that you expect, that MySQL/MariaDB only replicates the database that you've dumped and restored on the slave. But without filtering MySQL/MariaDB replicates everything from the master to the slave. To filter you can use the following manual page: https://mariadb.com/kb/en/library/replication-filters/

If that is not your problem, then the first thing I would check is, if someone has disabled foreign key checking on your master with select @@global.foreign_key_checks; If this returns 0 it's bad. Then you can use my stored procedure from this answer to check for data inconsistencies.