Cucumber Reports Plugin is not compatible with the Content Security Policy. Since Jenkins 1.625.3 and the implementation of SECURITY-95, Jenkins is unable to render JS components in the Cucumber reports (see attached screenshot and web console logs).

SECURITY-95: https://github.com/jenkinsci/jenkins/blob/jenkins-1.625.3/test/src/test/java/hudson/model/DirectoryBrowserSupportTest.java#L174
Content Security Policy: http://content-security-policy.com/
An "unsafe" workaround can be found here : https://wiki.jenkins-ci.org/display/JENKINS/Configuring+Content+Security+Policy