I have a 3-node cluster in MariaDB 10.3.10. I detached node 2 from cluster by restarting MariaDB using WSREP_ON=OFF defined in server.cnf.
After detached from cluster, I inserted new records in node 2. At the same time, I inserted several new records in node 1 and 3. The newly inserted records in node 1 and 3 could be sync among node 1 and 3, but not node 2 because node 2 was not cluster member.
Then I attached node 2 back to cluster by updating WSREP_ON=ON in server.cnf and restarted MariaDB. Node 2 joined back the cluster successfully.
I found that previously inserted records in node 1 and node 3 could be sync to node 2. But the new records in node 2 (inserted when node 2 was not cluster member) could not be sync to node 1 and 3.

Is it normal phenomenon for a previously detached node and now joining back the cluster?
What is the appropriate way to join back a previously detached node back to a cluster?

Now node 2 has more records than node 1/3.