(reported by user)

The short version:
I initiated 2 subsequent failovers upon creating a connection with multiple instance endpoints. The currentProtocol variable is null and therefore causes a NPE in the searchByStartName method (AuroraListener: line 194), which was called in the loop method of AuroraProtocol (AuroraProtocol: line 158). Adding a breakpoint on line 194 of AuroraListener helps tracing back. I would like to know why the currentProtocol is added to the blacklist.

Here is the relevant stacktrace:
java.lang.NullPointerException
at org.mariadb.jdbc.internal.failover.impl.AuroraListener.searchByStartName(AuroraListener.java:194)
at org.mariadb.jdbc.internal.protocol.AuroraProtocol.loop(AuroraProtocol.java:158)
at org.mariadb.jdbc.internal.failover.impl.AuroraListener.reconnectFailedConnection(AuroraListener.java:147)
at org.mariadb.jdbc.internal.failover.impl.MastersSlavesListener.initializeConnection(MastersSlavesListener.java:158)
at org.mariadb.jdbc.internal.failover.FailoverProxy.<init>(FailoverProxy.java:93)
at org.mariadb.jdbc.internal.util.Utils.retrieveProxy(Utils.java:455)
at org.mariadb.jdbc.Driver.connect(Driver.java:105)
at java.sql.DriverManager.getConnection(DriverManager.java:664)
at java.sql.DriverManager.getConnection(DriverManager.java:247)
…