No they are not scripted. Not like the WWE is. But I definitely think there are fighters who take a "dive". That's always the case in sports like that. Boxing for instance has had numerous scandals over the decades because fighters got paid to lose.
Being paid to lose and being scripted are two different things.
UFC no. Because they would settle on a good long reigning heavy weight champ if they were scripting it.
However it has been known in some of Japan’s mma to have fighters lose for the hype. Then again Japanese mma grew out of pro wrestling so it’s kind of understandable.
The closest to American mma doing something like that was EliteXC and it was only offering extra bonus if the fighter fighting Kimbo would win by KO. This encouraged, but not restricted, the fighters to fight stand up with Kimbo. When this hit the news(for influencing how the fighters would fight) EliteXC was destroyed, so I doubt UFC will pull off something like this.
there are fighters who take dives and stuff like that, but UFC is way different than WWE.
you can easily tell if fights are scripted, and not. besides there are actual injuries recorded from UFC matches. unlike something stupid like WWE.
Hope this helped man!