Get Distance To object along spline is not real distance?

Hi,

I am still trying to understand why the Get Distance To an object moving along the spline with the character does not show the real object distance but the original Spline position.

Example: I spawn many birds in a landscape and I place 1 Spline path in the landscape. In the BP, after a random delay for each bird, I use Set World Location to move the Spline to the bird location, and animate the bird along the path. All works perfectly.

However, when I measure the distance between the player character and the bird passing by, I get distances most probably related to the original position of the Spline and not the physical position of the bird.

I could verify this by setting the character closer to where the Spline is placed in the level.

However, The Get distance to is working with logical numbers if measured with the bird on the ground before they use the Spline to fly.

I thought with the Set World Location the Spline move its position and coordinates to the bird position but it seems that it is not the case?

Any idea?

Thanks