According to the code inspection, there is a JEP-200 issue in the plugin: https://github.com/jenkinsci/gatling-plugin/blob/775b494c4ba020018d0aef24316f844e47e0bb32/src/main/java/io/gatling/jenkins/GatlingPublisher.java#L44
This code likely causes a JEP-200 issue when the object gets persisted to the disk. "java.io.PrintStream" is not whitelisted in Jenkins for a reason, because loggers are not expected reliably after being deserialized from the disk.
Useful links about JEP-200:
- Blog post for users: https://jenkins.io/blog/2018/03/15/jep-200-lts/
- JEP-200 guidelines for plugin developers: https://jenkins.io/blog/2018/01/13/jep-200/#for-plugin-developers