How does the Vector Math Normalize node work? As I understand, the normalize setting should convert a vector into a unit vector. However, I am confused as two what the second vector input does in this operation. Normalizing should only require one vector input right?
For the normalize option the node will only normalize the first input vector (set the length to 1). You are right, a second vector isn't needed for this operation.

This example shows how it can be used to multiply a vector by a scalar: