It is one thing to decrypt and re-encrypt when you are man-in-the-middle of the comms. That’s not the case here. There are some protocols and key management that support a third party being able to recover encrypted comms, but they are in the encryption protocols being considered and deployed in ICS. And I’d put this in the bad idea category.
This is an admittedly future reason why gathering information through protocol commands, what I’m referring to as Active, is important.