s needed if a slave becomes diverged from another server so
that two different GTIDs with the same seq_no (in the same domain) arrive at
the same server. This situation is in any case best avoided; setting
gtid_strict_mode is recommended, as this will prevent any such out-of-order
sequence numbers from ever being replicated on a slave.

URL: https://mariadb.com/kb/en/master_gtid_wait/https://mariadb.com/kb/en/master_gtid_wait/