"leased not associated" error on instance delete

In a (folsom) system that appeared to be working normally, I saw this error in the log after deleting an instance.

Oct 23 13:00:45 se01-2eth0 2012-10-23 13:00:45 ERROR nova.openstack.common.rpc.amqp [-] Exception during message handling#0122012-10-23 13:00:45 TRACE nova.openstack.common.rpc.amqp Traceback (most recent call last):#0122012-10-23 13:00:45 TRACE nova.openstack.common.rpc.amqp File "/usr/lib/python2.7/dist-packages/nova/openstack/common/rpc/amqp.py", line 275, in _process_data#0122012-10-23 13:00:45 TRACE nova.openstack.common.rpc.amqp rval = self.proxy.dispatch(ctxt, version, method, **args)#0122012-10-23 13:00:45 TRACE nova.openstack.common.rpc.amqp File "/usr/lib/python2.7/dist-packages/nova/openstack/common/rpc/dispatcher.py", line 145, in dispatch#0122012-10-23 13:00:45 TRACE nova.openstack.common.rpc.amqp return getattr(proxyobj, method)(ctxt, **kwargs)#0122012-10-23 13:00:45 TRACE nova.openstack.common.rpc.amqp File "/usr/lib/python2.7/dist-packages/nova/network/manager.py", line 1339, in lease_fixed_ip#0122012-10-23 13:00:45 TRACE nova.openstack.common.rpc.amqp raise exception.NovaException(msg)#0122012-10-23 13:00:45 TRACE nova.openstack.common.rpc.amqp NovaException: IP 172.26.0.2 leased that is not associated#0122012-10-23 13:00:45 TRACE nova.openstack.common.rpc.amqp
Oct 23 13:00:46 se01-2eth0 2012-10-23 13:00:46 ERROR nova.api.metadata.handler [-] Failed to get metadata for ip: 172.26.0.2