Is this a bug ?

I have an approval activity of Group type. I have a two role owners who should approve the request and if they fail to do so it should escalate to their manager and respective email notification should be triggered . When I submitted the request, both owners received email notification for approval , also both of them had approval activity in their dashboard. . I have used '_default_' in 'TO'.

Now, both of them did not take any action for x number of days, so workflow is suppose to get escalated , it is suppose to send email notification to their managers for approval along with approval activity to manager's dashboard. Here is what happened.. Escalation email did not go to managers at all, in fact mails were again sent to actual role owners, however approval activity got escalated and it is in manager dashboard, which is weird. Remember I have used _default_ only in TO. (No custom code)

In escalation addressee I have used default escalation address . IDVault.get(Activity25.getAddressee(),'user','mana ger') .

1. Mail did not go to managers in escalation . Instead it went to actual owners again.
2. During escalation, approval activity only went to one owner's manager. It is suppose to go to both user's manager.
3. If I use java.lang.System.out.println(Activity25.getAddress ee()), I am getting only one owner's DN. During escalation also I am getting same owner's DN. And If change the approver type from Group to Normal, I am getting owner's manager DN in logs during escalation. So over all everything works fine if approver type is Normal. But my requirement says , I must have group approval.