The NodeLabeler plugin automatically labels nodes based on various permutations of their operating system name, architecture, and version. If I insert a comma separated list of labels where the same label matches more than once on a node, that node is included in the elastic axis plugin based axis definition multiple times.

For example, my Windows 7 slave machines all have the labels "windows" and "windows-6.1". If I define an elastic axis on a job with "windows,windows-6.1" then the machines which match those labels will be listed twice and executed twice on that machine.

It seems like the list of machines returned should have duplicates removed.