Connection via Connector Java 2.2.4 randomly fails with 'could not load system variables'

Simple connection to MaxScale 2.1 via JDBC 2.2.4 fails with:

could not load system variables

Using JDBC 2.1 succeeds, as well as using MaxScale 2.2 with any JDBC version.

                  MaxScale 2.1    MaxScale 2.2

JDBC 2.1                OK              OK

JDBC 2.2                ERR             OK

If I add `usePipelineAuth=false` parameter to Java the problem disappears.