How can I set a default Spline User Parameter on Niagara System.

Hello everyone.

I have a Niagara System in which I have created a scratch pad module with a Spline input.
I use that to spawn the particles based on Sample Spline Unit Distance. Later, I set the Spline parameter as User Parameter. I create the Niagara and Spline actors in the scene, I pass the spline as parameter to the niagara system and voila, the particles are generated based on the spline. Everything works as expected.

The problem is that I cannot set a default spline in the Spline User Parameter in the Niagara System.
There, I switch to “User Parameters” tab, I see the spline parameter, and as I click the dropdown to select my spline, it is not accepted and it is set back to “None”.

Any idea if this is some kind of a bug ?

Thank you for your time everyone and have a nice day.
P.