I was not able to get the UnexpectedRollbackException that is mentioned in the jira. I was however getting three other exceptions which were causing it to blow up
1. ArrayIndexOutofBounds exception at History.buildHistoryFromParameterString()
pushToHistory(params, params, params, params, params);
2. NullPointerExeption at AgendaEditorMaintainable.retrieveTermParameters()
Tree<RuleTreeNode, String> propositionTree = rule.getPropositionTree();
3.ExceptionEvaluationError at ExpressionEvaluatorServiceImpl.evaluateExpression() because it was retaining the pageId from the EditRule page.
Expression expression = parser.parseExpression(expressionStr);
I have added a fix for each of these and will create a review for it. Breadcrumbs on the Agenda Editor are no longer blowing up and it takes you back to the AgendaEdit page with the initially selected agenda.