To reproduce:

• Run blue ocean, open http://localhost:8080/jenkins/blue/pipelines/ - leave open in a tab
• Restart it
• go back to http://localhost:8080/jenkins/blue/pipelines/ and try to click on a pipeline, open it, open a run etc. Keep an eye on browser console and you will see auth errors in the api, but the GUI will not log you in until you refresh the whole page.