OnTaskChanged Event is not firing in State Machine Workflow

Hi SharePoint Experts,

I am developing a visual studio 2008  state machine workflow in which I am using custom aspx Task form for approving/rejecting a task. There are 2 levels of approvals.

If approver1 approves then it will create a task for approver2 for his/her approval.

If approver2 approves then workflow is completed.

If approver2 rejects then it will route back to approver1 and creates task for approver1 for his/her approval.

When approver1 approves/rejects task via custom aspx task form then ontaskchanged for approver1 is firing perfectly fine.

But if approver2 approves/rejects task via custom aspx task form then ontaskchanged for approver2 is not firing.

I restarted the Windows SharePoint Services Timer service and tried to debug the workflow then ontaskchanged event for approver2 is firing couple of times and not firing some times.

Even though if ontaskchanged event is fired when approver2 rejects and executes the createTask activity for approver1 the task for approver1 is not getting created.

Please help me how to resolve this issue.

Thanks,

Hidayat