I just realized that with 17.2 (but may be the case since a long time), if you have a host name like x-y.dom.ain, the host entry added in the DHCP configuration will be x.dom.ain-y. This is basically harmless but a litle bit surprising... Is it a design choice or a bug?
If this is a bug, when fixing it, it should continue to search for the buggy name when deleting a name to allow an easy cleanup of the problem...