Some assets in viewport not visible in the movie render queue.

Hi there,
I have a scene that I’d like to test render but no matter what I do some assets refuse to show up in the render preview of the movie render queue. I’ve tried everything I know and nothing works so far, would really appreciate some insight from some of you guys.

Basically every element inside the hourglass piece as well as the niagara particle system is not displayed.

I tried game overrides, disabling LODs, checked that the actors are not hidden in game and I don’t really see why these would not render.

Let me know if you have any more leads for me, thanks !