Path must have a length of at least 2?

My English is not good
Wonder why my OnPathComplete returns PATH sometimes path.vectorPath.Count == 0
I use ABPATH i write your own movement script
The Simple Smooth Modifier component was a little better when I removed it but sometimes I still got an error(Path must have a length of at least 2)

*What are the conditions that cause path.vectorPath.Count to be 0?

I tested it a day today and it seems that when using multiple threads, the vectorPath.count is sometimes zero
thread count = none There will be no error (MY Time.timeScale = 5 test)

My error has a place that references path.vectorPath and calls clear