When you create a branch, delete it and then try and get Jenkins to checkout the branch at a revision at which it did exist the validation fails and the checkout fails on build.

This is because the checkout command in CheckoutUpdater.java uses HEAD as a parameter instead of the revision given:

svnuc.doCheckout(location.getSVNURL(), local.getCanonicalFile(), SVNRevision.HEAD, r, svnDepth, true);