Issue
After upgrading Microfocus Automation Plugin to 7.4, editing and saving of Pipelines no longer displays the Pipeline script.
If I try to save the job configuration from the UI, the following Warning is logged:
WARNING hudson.model.Descriptor#verifyNewInstance: Father of org.jenkinsci.plugins.workflow.cps.CpsFlowDefinition@7be8c613 and its getDescriptor() points to two different instances. Probably misplaced @Extension. See http://hudson.361315.n4.nabble.com/Help-Hint-needed-Post-build-action-doesn-t-stay-activated-td2308833.html
Resolution
The issue was solved in Microfocus Automation Plugin version 7.4.3. Thus, the behaviour can be avoided either by upgrading it to release 7.4.3 or newer, or downgrading to an older version.
Remember that before any modification is to be applied to a Jenkins instance, for example a plugin version update, it is recommended that you test the changes in a lower environment and that you take a backup of the current installation to be able to revert the changes if something would not work as expected.