After upgrading from 1.488 to 1.491 (could not test the others because of a bug with mercurial) one of our builds started to fail. It is a multi-config build with two axes, one of which is a workaround to get the "restrict where the project can be built" functionality which is not available for multi-config builds. It is a "Slaves" axis with only the Jenkins master node selected. However, the project always seems to be built on a windows node which doesn't even have mercurial installed.