metadata service returns 500 error

Starting an instance, trnasitions to running state - but ssh fails to work. Seems metadata service is returning 500.

Extract from log, that seems pertinent:
==> cloud-error.log <==
00:12:34 ERROR [NioServerHandler:New I/O server worker #1-10] Internal Error.
com.eucalyptus.context.NoSuchContextException: Found channel context [id: 0x77dc7e18, /172.19.1.2:49179 => /169.254.169.254:8773] but no corresponding context.
        at com.eucalyptus.context.Contexts.lookup(Contexts.java:29)
        at com.eucalyptus.ws.server.MetadataPipeline.handleUpstream(MetadataPipeline.java:72)
        at com.eucalyptus.ws.server.NioServerHandler.messageReceived(NioServerHandler.java:127)
        at org.jboss.netty.handler.stream.ChunkedWriteHandler.handleUpstream(ChunkedWriteHandler.java:114)
        at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:385)
        at org.jboss.netty.handler.codec.replay.ReplayingDecoder.unfoldAndfireMessageReceived(ReplayingDecoder.java:459)
        at org.jboss.netty.handler.codec.replay.ReplayingDecoder.callDecode(ReplayingDecoder.java:443)
        at org.jboss.netty.handler.codec.replay.ReplayingDecoder.messageReceived(ReplayingDecoder.java:381)
        at com.eucalyptus.ws.handlers.http.NioSslHandler.handleUpstream(NioSslHandler.java:31)
        at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:342)
        at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:329)
        at org.jboss.netty.channel.socket.nio.NioWorker.read(NioWorker.java:330)
        at org.jboss.netty.channel.socket.nio.NioWorker.processSelectedKeys(NioWorker.java:282)
        at org.jboss.netty.channel.socket.nio.NioWorker.run(NioWorker.java:203)
        at org.jboss.netty.util.internal.IoWorkerRunnable.run(IoWorkerRunnable.java:53)
        at org.jboss.netty.handler.execution.MemoryAwareThreadPoolExecutor$MemoryAwareRunnable.run(MemoryAwareThreadPoolExecutor.java:502)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
        at java.lang.Thread.run(Thread.java:636)

Full logs, as reproduced by hggdh2:
 lp:~hggdh2/+junk/uec-qa (r55)