pprkut there are certainly some stage behaviours with the Bitbucket branch source with Blue Ocean. I suspect there is some encoding issues on the Bitbucket branch source that are related to JENKINS-41407 that could be the root cause here.

Bitbucket support is coming up on our roadmap soon and we hope to clean up a bunch of problems like the one you are describing. I've added this to our Bitbucket Support epic.

pprkut I just played around with jobs with slashes in it and it looks like we are now encoding things correctly with the latest Bitbucket and Blue Ocean plugins.

See screencast https://www.dropbox.com/s/50v49xwyz6fqkvl/url-paths.gif?dl=0

pprkut I am going to close this for the moment however if this is still a problem for you and you can provide me some step by step reproduction instructions I'd be more than happy to take a deeper dive

Is this with the latest code in git or with the latest releases? I just applied all available updates here, but that didn't seem to change anything.

pprkut I used all the latest plugins and Blue Ocean 1.1-beta4 from the experimental update center.

Ok, so with the latest beta versions I can confirm that URLs are working correctly in Blue Ocean.

However, going from Classic to Blue Ocean via the "Open Blue Ocean" URL is still not working. What happens is this:
The link in the classic UI is: https://jenkins.example.com/blue/organizations/jenkins/bb%2Fproject/branches
This returns a 302 response code, with a Location value that's now wrong: https://jenkins.example.com/blue/organizations/jenkins/bb/project/branches/
(Note the slash at the end, which is the actual reason for the 302 redirection)