It's like I said "Your car is missing a rear mirror." and you want me to provide you a description of rear mirror and send a picture of rear mirror to your engineer so they can understand what a rear mirror looks like.
Sorry, I don't want to insult your software engineer like that. It was probably not their fault that the HSBS is played at the wrong aspect-ratio. I guess the AV Pro plugin in Unity is the real reason this happened.