Expense Report Problem

Hi,

Expense Reports showing as approved without getting approved by managers.Users getting the notification as expense report has been approved and when I checked in the Workflow Administrator responsibility not able to find the approver notification in Participant Responses tab and Activity History of Request approval from approver is not in Activity history also

One user has submitted Expense Report in front of me and he immediately got one notification saying that expense report has been approved by your manager with fraction of seconds and it has been replicated with few users also.(Unfortunately no manager got the notifcation to approve the expense report)