Different sequence of the game (Grand Theft Auto 5)

Hello! Faced the problem that missions are not issued. After I finished the Chop mission, I did tasks from Tony, traveled in races and that's all, no longer issued. I climbed all the forums, tried to find the answer - I couldn't find it. Suddenly, a random sequence of missions popped up to me. There I saw that Chop is mission 6, but I only completed 4. How did it happen? Help me please!