After doing a build there is an option to resubmit the build with the exact same revisions. This generates an exception (at least in the case where the revision is pointing into poky-contrib and branch != master. Steps to reproduce: build nightly-qa-systemd-load use git://git.yoctoproject.org/poky-contrib and branch = rewitt/systemd_debug_off after the build is done, goto the bottom of the page and use the rebuild button with exact same revisions. The queued build shows an exception.
Yes, that button should be removed from the UI. It was removed prior to the bb upgrade and has snuck itself back in.
Patch submitted to the mailing list: https://lists.yoctoproject.org/pipermail/yocto/2016-February/028507.html
Marking this resolved fixed. Patch has been pulled into master. Once there is a window, it will be pushed to production.