Problem with "RESTful API Client" plugin and multiple calls

Hello there,
I’ve successfully implemented REST API calls in my tests by using “RESTful API Client” plugin.
Each test prepares the test pre-conditions via a REST API call, and then the navigation on the web pages starts.

Unfortunately, if I package the tests in a job, and then I run the job, starting from the second test the REST API call step fails with message: “java.lang.IllegalStateException: Already connected”.

I think that this is maybe due to a bug in the plugin Java client, as this kind of issue is frequently reported in the Java forums.
Can anyone help us?