Clean up old Domain Name for Nodes in Puppet Dashboard

I changed the domain name for some servers, i.e. web1.foo.com to web1.baz.com. In my Puppet Dashboard, I see two entries now for the same server.

I can destroy a node with something like rake node:fast_del name=web1.foo.com which seems to work (the web interface destroy doesn't work, see http://projects.puppetlabs.com/issues/6828) but only temporarily, eventually the old domain comes back. I checked facter on the host and I don't see any sign of the old domain in there, any idea why the old domain comes back?