I am beginning to agree... ALTHOUGH I also wonder if this might be a correction of past interference that may have caused the guy to die originally, now.
Wouldn't it be kinda cliché, though? I'm tired of all the "time travel is bad" trope. Even so, if Yeon-ho interfering causes the accident, isn't that saying that infinite versions of himself are continually stuck in a multi-universal time loop. He would then cause the accident again and again and again to a different Jaeha living in another universe.
I hope it isn't the cause either. I could see it going in a way that although he's able to keep him alive, they don't ultimately end up together. It's just all so teetering on the edge right now. All these resolutions Yeon-ho is making with his life feel like a great high before a tragic low.
I said it before and I'll say it again..feels like him interfering will be the cause of the accident.