Why are some numbers skipped when trying to implement multithreading?

Question

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Explain, I wanted to multithread, but in the end it skips some ranges, skips, and even freezes from 1000 threads, + why different threads take the next digit one by one, but although it was planned to divide into several small ones
https://github.com/sdigi/VkDockSearch /blob/dev/VKD...

Answer 1

for (int i = 0; i < taskCount; i++)
{
  Thread thread = new Thread(ParsingDocUserIdAync);
  p[1] = docStarId;
  p[2] += (int)offset;
  thread.Start(param);
  docStarId = p[2]+1;
  list.Add(thread);
}

You start threads by passing the same array as an argument, while changing it from the outside ( pand paramare the same object).
The call thread.Start(param)does not guarantee that the thread will be created and start executing immediately.