Invoice Workflow From Attribute Set to Null

Hey Guys,

when ever I create an AP Invoice , the from attribute in the notification is set to null. In the wf_item_attributes table for item type of APINVAPR i don't see any attribute related to the from. In ap_invoices_all the transaction_requester_id is populated to requester value. In the notification detail page the from_role is populated to Account Payables. As the from attribute is set to null I am facing issues like when approver request for more info its going to Account payables and  no action can be taken and also not able to identify the notification is sent from which user.