iterators, debugger stops after second cycle

[naitse]

example mule code:

                       <collection-splitter/>
                            <message-properties-transformer scope="invocation" doc:name="Message Properties">
                                <add-message-property key="gitHubCommentIdInJiraIssue" value="#[groovy:payload.body.split(' | ')[0]]" />
                            </message-properties-transformer>
                            <github:get-comments config-ref="Github" user="mulesoft" repository="#[groovy:message.getInvocationProperty('gitRepoName')]" issueId="#[groovy:message.getInvocationProperty('gitIssueId')]"/>
                           <script:component>
                               <script:script engine="groovy">
                                        <script:text>
                                            return payload = "blablabla"
                                        </script:text>
                               </script:script>
                           </script:component>
                            <debugger:breakpoint/>


                        <logger message="issue already on jira #[payload:]" level="INFO" />

console result:

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

• Mule is up and kicking (every 5000ms) +
  ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
  INFO 2012-04-10 18:10:29,303 [[GitHubIssues2Jira-1.0-SNAPSHOT].GithubIssues2Jira.stage1.02] org.mule.api.processor.LoggerMessageProcessor: issue already on jira blablabla
  response = org.mule.debugger.response.MuleMessageArrivedResponse@530a3ffc

as you may see, the debugger cycles one time and then it stops the flow