Help me understand MoveTowards()

Whenever I use MoveTowards() in the same way as shown in the Unity documentation, I get double the move speed.

transform.position = Vector3.MoveTowards() //moves twice.

Whenever I use it this way, I get normal, accurate speed

Vector3.MoveTowards() //moves once

I do not understand why. If I do the first method twice in a row, will it double the speed because I called the method twice? If so, why does the second method not do the same?

What is actually going on under the hood?

Race conditions with Unity’s NavMesh were making me think that Vector3.MoveTowards() did more than just return a Vector3.