Hello,
the only way I know of this could happen is when the switch has previously been a member of a cluster...check the info below. Which IOS version are you running on the 3560 ? This could be a bug, I will check that, can yo post the output of ´show version´?
Hostnames
You do not need to assign a host name to either a cluster command switch or an eligible cluster member. However, a hostname assigned to the cluster command switch can help to identify the switch cluster. The default hostname for the switch is Switch.
If a switch joins a cluster and it does not have a hostname, the cluster command switch appends a unique member number to its own hostname and assigns it sequentially as each switch joins the cluster. The number means the order in which the switch was added to the cluster. For example, a cluster command switch named eng-cluster could name the fifth cluster member eng-cluster-5.
If a switch has a hostname, it retains that name when it joins a cluster and when it leaves the cluster.
If a switch received its hostname from the cluster command switch, was removed from a cluster, was then added to a new cluster, and kept the same member number (such as 5), the switch overwrites the old hostname (such as eng-cluster-5) with the hostname of the cluster command switch in the new cluster (such as mkg-cluster-5). If the switch member number changes in the new cluster (such as 3), the switch retains the previous name (eng-cluster-5).
Regards,
GP
