Stats graph truncates long OS descriptions.
In the stats graph, if you have a OS with a long name, such as "CentOS Linux 7.1.1503", it will shorten the string to "CentOS Linux ...". This includes when you click on the slice in the graph to drill down into the list of hosts. So you end up with a broken search, like: os_description="CentOS Linux ...". This happens for RHEL too. e.g. os_title="Red Hat Enter..."
This bug has been seen in the 1.6-stable branch as well as 1.9-develop.