I assume you mean the game itself is running poorly? Not just the video playback when it recorded?
Do you and your friend have similar hardware specs?
I'd recommend sending in client logs in a ticket if you haven't done so already: LINK
Thanks for making that. So in regards to the game not running well, I'm not 100% sure. Although with your logs (and a few others) found that essentially the same problem that others are having with Rust, is probably affecting Dead by Daylight as well. I'm seeing 2 instances of exes; one we detect, and the other we do not. It's possible that the client is somehow getting around Easy Anti-cheat and just hooking in via software encoding. However, whatever it is doing is possibly causing that lag.
We're in contact with Easy Anti-cheat though and hopefully will get a solution from them.