+++ This bug was initially created as a clone of Bug #1148943 +++ --append="console=ttyS0,115200 console=ttyS1,115200" should be removed from guest kickstarts. This was done in 0.18.2 but regressed in 0.18.3. See the original bug for full details.
http://gerrit.beaker-project.org/#/c/3431/