Why SimpleMoveToLocation can't work correctly?

when i use SimpleMoveToLocation to find path in my map,i choose a reachable point(14651, 19915, 265.8), it always works all right,but sometimes it stop at a wrong position。

the code :
FVector vect = FVector(14651, 19915, 265.8);
GetWorld()->GetNavigationSystem()->SimpleMoveToLocation(this, vect);

but it stop at(1102, 1862, 180);

as the log

91303-1.png