Set beam End Point not working

I have been working on making a beam effect for a line trace wep. At first I had the Actor component on the player the handles the input and targeting logic also spawn in particle systems in the world. However I could not get lifetime and it was pretty messy looking code so I decide to make it spawn in an actor that has the particle systems in it so it was easier to manipulate the life time of the effect. I have then end point a variable that is exposed on spawn. and in the construction script of the the actor I have it set beam end point. However for some reason the beam is still going to 0 0 0. Even though I no the endpoint is valid, because the hit effect is going to the right location.

I should mention that there is a work around for this problem, that I know about witch is setting the endpoint outside of the construction script. Like in an event graph. I am mostly posting because I want to understand why this does not work.