Pipeline script post handler - changed action always fired

In a pipeline script I have the following post handler logic.

   post {                                               
       always {                                                          
           junit 'results/*.xml' 
       }                             
       changed {                                                      
           emailext body: '$DEFAULT_CONTENT', subject: '$DEFAULT_SUBJECT', to: 'email@domain.com'                                             
       }                                                            
   }   

What used to happen is that emails would only be sent if the state changed. So if the build results were as follows

• FAILED
• UNSTABLE
• UNSTABLE
• UNSTABLE
• FAILED
• UNSTABLE
• FAILED
• UNSTABLE
• UNSTABLE

Then email would only be sent on the state change from UNSTABLE->FAILED or FAILED->UNSTABLE. Emails would not be sent when the state was UNSTABLE->UNSTABLE.

However our Jenkins server was updated over Christmas and as a result I am seeing an email being sent regardless of the state remaining the same. I could work around this by using something similar to

if (currentBuild.currentResult.toString() != currentBuild.getPreviousBuild.getResult().toString()) {
// email
}

However the previous behaviour was what I was expecting to see. Changes in the pipeline plugins seem to be