[SalesForce] Not able to change case owner to current owner’s manager using process builder

I need to be able to change case to current case owner's manager using standard manager ID field on User object. As shown in the screenshot below.
Process Builder

I am getting following flow error every time flow executes and meet entry criteria.

This error occurred when the flow tried to update records: The flow failed to access the value for myVariable_current.Owner:User.ManagerId because it hasn't been set or assigned.. You can look up ExceptionCode values in the SOAP API Developer Guide.

I made sure that my manager lookup on user record is populated with value.

I have also tried creating formula field on case to get owner manager id and try changing owner with that id but I am getting the same error. Please note that I am system admin and have Manage internal user permission.

Can someone please help me resolving this issue?

Best Answer

https://jenwlee.wordpress.com/2018/01/16/the-flow-failed-to-access-the-value-for-myvariable_field-because-it-hasnt-been-set-or-assigned/

I've experienced this before where I swear process builder would throw an error on a related objects' field even though the field has a value. I included the post above to show this is not just something I made up.

I think a good test would be to (in a test environment), just create a formula field on case that includes the Manager ID of the owner of the case to confirm that process builder can change owner with a custom field on the same object without error. This way, you can isolate the issue to navigating through the related object.

Whether this is a necessary workaround, I'm not sure. It might be worthwhile to put in a case with Salesforce or test out activating the critical update concerning process builder and relationship fields (this is related to null values, but worth it in a dev box to give it a try to see if it helps).