What is the Reason for EBSUser responsibility validTo date being set.

Hi Team, 

We are observing the following behavior in EBSUser responsibility table. 

When the EBS sync is being run we have seen for some users the EBS user responsibility ValidTo date in EBSUserInResp table is being set and that is triggering De provisioning of that EBS responsibility. The mapping present is also direct without any script on it. Also there is no value template on the ValidTo column . But the thing that we are unable to understand is what is causing the ValidTo field to be set. 

Any ideas or suggestions would be very helpful. 

Thanks and regards, 

Sudhir