ERES: Is the Authentication and Approval process limited to the requester's session and device ?

We are using Oracle EBS 12.2.13 with OL7 and DB version 19c.23. We've implemented the setup for Electronic Records and Electronic Signatures, starting with the "Miscellaneous Receipt transaction."

General Question: Why approver need to approve transaction from requester computer, and can't approve from his (Approver) office, computer and his own session, suppose both requester and approvers in different building or area?

Example:

When we attempted to create a Miscellaneous Receipt, the following occurred:

1. The requester clicked on the Sign button.
2. The approver couldn't approve e-record event he received into WF Notifications, an error page stating "You have encountered an unexpected error" appeared.