This is actually tied with a page design issue. When you go to a pipeline execution page, the Jenkins link in the top right disappears, so it's not easy to get back to the main page. You have to click the pipeline name to get back one level. This should in my opinion be a breadcrumb trail allowing you to go up all the way.
Anyway, the main issue: clicking the Jenkins link triggers a full page refresh on Firefox 58, at least. I don't really understand why, Blue Ocean should be an SPA, so it should have no full page refreshes?