This error seems to be unrelated to the issue being reported. Could you share the JSON being used and logs upto 100 lines before and after you observe the error.
I have validated the above expression in one of the environments and it's working as expected. This might be an issue with the data. Maybe try with a different entitlement or different set of data.
Hi @Suyash_Badnore1 ,You may want to try the following binding to fetch the user's manager's email address.${com.saviynt.ecm.identitywarehouse.domain.Users.get(user?.manager)?.email}