Could be this has been fixed since, but just in case, thought I'd report it - when I go to, say, https://ci.jenkins.io/blue/organizations/jenkins/Plugins%2Fpipeline-model-definition-plugin/activity/, the duration for any currently running build starts at 0 seconds and counts forward. Then, if I reload the page, the duration resets back to 0 again. This isn't the case for completed builds, just running builds.