Thanks @anon95708182 - appreciate the help. I see how it works and realize that this is just the way it works.
Basically just need to make new spline collections for each instance.
Seems a shame that there’s no way to make a reusable spline “widget” (or any other type of widget) where you can just drop it into the level and manipulate because it’s a new instance and not modifying the original “prototype”.
Still thx for the good explanation of how it works!