GTID server-id in Galera set-up changed

Since we recently upgraded all our MariaDB/Galera clusters from 10.11.7 to 11.4.2, we noticed that the second part of the GTID for Galera set-ups changed.

As per documentation we choose to set a different server_id on each cluster node. This way we can track each transaction down to the originating node in our binlog analysis tooling.
https://mariadb.com/kb/en/using-mariadb-replication-with-mariadb-galera-cluster-using-mariadb-replica/#setting-server_id-on-cluster-nodes
https://mariadb.com/kb/en/gtid/#implementation

Relevant config node1

gtid_domain_id = 10168

server_id = 10168

wsrep_gtid_domain_id = 10160

Relevant config node2

gtid_domain_id = 10169

server_id = 10169

wsrep_gtid_domain_id = 10160

Relevant config node3

gtid_domain_id = 10170

server_id = 10170

wsrep_gtid_domain_id = 10160

DML on node2

UPDATE t1 SET b = 'b' WHERE i = 1;

Binlog on all nodes

#240705 12:00:38 server id 10168  end_log_pos 1314 CRC32 0xb816275b     GTID 10160-10168-4015672 trans

As you can see, the second part (server_id) corresponds with node1 and not with the originating node2.

I'm not sure which server-id is used, possible that from the first (bootstrapped) node.

The change doesn't break replication (since domain-id and seqnr is the unique part), but is does break the tracking of originating node.