The subflow is getting called from ITOM framework through mapping. 
I changed the selection from catalog task to RITM and again tested the flow. I got the same error.
We are using ITOM process and we have added mapping for automation enabled. This subflow is created to run the automation for one of the requirement. The subflow is not directly getting called from the catalog flow but from Mapping flow. We can get info about the RITM and Catalog from that. I compared the value of the MRVS in both catalog flow and the automation subflow, it is same.