The first fight was so one sided it's hard to see a different result.
Merab is old for the division though so he could fall off a cliff randomly one day and not look the same anymore, but there isn't really any signs of that, he looks as good as ever in his last couple of fights.
It's combat sport though so weird things can happen, it only takes one strike to change everything. Yan not being a big KO artist though it's unlikely.
It's almost impossible to win a 5 round decision against Merab, you really do need some god tier TDD and a lot of attributes to go along with that. You spend all your time defending 50 takedown attempts, even if you defend them well you don't win rounds by defending takedowns, and you can't get any offence going when you're defending 50 takedowns. Yan's high guard really invites Merab to shoot for his legs.