Actually I have crashes in every race in Moto3, Moto2... I put rider Min-Max Dry(Wet)Skill values like 0.45 - 1.00, so for example, J.McPhee has min-max range 0.68-1.00, but weak riders like Pizzoli 0.46-0.95... I noticed, there is significant number of crashes at the start of race, and near the end of race... Races are fun - a lot of winners (Rodrigo, Binder (before he won in real life)), but - never Rossi, or Pizzoli or Dupasqier, so there is realism, at the same time fun.
Crashes are caused by collisions when at some stage of race some rider can become slower, he brakes earlier, another AI rider, who does not have speed problems, is too fast and crashes into that slower guy... it is quite impossible to guess who will be victim. I noticed that this wide skill range (like 0.50-1.00), causes any rider
1) be slow at the start already... but sometimes he can become very fast later (!!!) so I assume that this RaceSkill changes dynamically throughout the race. Many many variations happen.
2) be fast at start, become slower at the end of race (tire wear can be a factor as well)
3) be slow all the time, be fast all the time, etc..... Many many variations happen.
During wet races there are also high-sides in Moto3.