Yan lost his title because he made a very stupid mistake, he could have let Aljo up, but he decided to keep him on the floor and play a stupid game that ultimately got him disqualified. If you don't fully understand the rules don't play that game where you won't let your opponent get up. Usman was doing to Gilbert what Yan was trying to do; the difference was Usman understood the rules and was careful not to violate them; not knee his grounded opponent in the face.
I have no doubt Yan will win his way back, but let him fight Sandhagen for a title shot. And let Aljo defend his title versus the guy who vacated it less than a year ago.