The source failover procedure ignores the suggested new candidate for promotion if you click on the right side of the hostname (the TCP port part), as in the example below:

After the promotion, instead of node 22738, the other replica with port 22739 gets elected instead:

Tested with Orchestrator 3.2.6 and both simple flat replication topology as well as chains. In all cases the wrong behavior is repeatable. Clicking on the left side of the hostname results in the correct replica being elected.
The source failover procedure ignores the suggested new candidate for promotion if you click on the right side of the hostname (the TCP port part), as in the example below:

After the promotion, instead of node 22738, the other replica with port 22739 gets elected instead:

Tested with Orchestrator 3.2.6 and both simple flat replication topology as well as chains. In all cases the wrong behavior is repeatable. Clicking on the left side of the hostname results in the correct replica being elected.