Workflow pre post images empty

Hi there,

I've a workflow which triggers on demand/automatic when opportunity status changes, recently I found this workflow not working properly. when I try to replicate the post/pre entity images are null in both the cases.

The workflow has an input parameter entity reference Account (customerid) it is also null.

On-pre setup.

MSD CRM 2013

Any suggestion for this issue.

Thanks,

Kiran.