Darius Ult Gameplay Issue

(reposting with new title because my last one made it look like I was posting a Darius play I made) I really don't like Darius, I feel there's next to nothing you can do to outplay him, especially his ult. I don't want to make a rant though and I came to mention something specific, so I'll just focus on his ult. It's incredibly strong, which would be fine if it felt like you could do something about it. whenever you flash, dash far away or knock Darius back, I really feel his ult shouldn't be allowed to still hit you because he definitely does not have difficulty catching people in the first place. What I show in this video however is something that I am confident was not intentional, and if it is, it feels like a horrible and unfair gameplay choice. Camille's ult cast gives her a small moment of invulnerability, so you can use it to avoid things similar to Shaco's (is he a victim to this too?), which would make it one of the very few things that can deal with Darius ult, except it doesn't. His ult instead simply comes back up and he can use it again.

I am not defending Camille either, she is overly strong but is extremely fun so I am looking forward to her feeling more balanced but she should absolutely be able to dodge Darius ult when she reads it or has really good reaction.