Hey, this has happened to me twice on two different Ubuntu 10.04 servers running a fresh install of Jenkins 1.457.
I install the Git and GitHub plugins and configure my new Jenkins job to build when it receives a push notification from GitHub. In the job config I leave "Branches to build - Branch Specifier (blank for default):" blank, which sets the value to **, which according to the help means "all branches will be examined for changes and built." What happens is that every time a build starts (whether started by a GitHub notification, periodic timer, or manually) it picks a random branch and builds that. Different branch every time. No relation to which branches have changed recently in the GitHub repo. Our GitHub repo has over 200 branches on it, most of them old branches that haven't changed in ages. My theory is that the new job sees every branch as new/changed and has to build each branch once before it will settle down and start building only the changed branch. Does anyone else know what might be going wrong? Will building 200 branches fix the problem? Might there be any other way around it? I'm currently having it build every 10 mins to see if it will eventually settle down. Thanks