I recently bought a 800E 4K Bravia, though I suspect this is not just a problem with this one TV/ remote, and after updating the software on the TV the remote and buttons work simultaneously with the Trinitron tube TV in my room.
I had to unplug the trinitron while I figure this out, but I need that older TV for old console gaming. I tried going through the Bravia universal controls, but I'm afraid I don't know enough about it to explore too much. Nothing I did worked and I could really use some advice if anyone else has had this issue.
TL;DR - I need my 4k TV remote to only control that TV and not work on my old trinitron. Please help.