i have the same crash and when you make the emitter cpu the problem goes away, it turn’s out that the problem is when you have a hard reference for niagara particle system with GPU it crash the packaged game, and only for certain actor, for example:
i have hard reference of niagara particle system in the character class and another one in weapon class when you remove it from the weapon class the problem goes away.
try remove the particle from any reference and if the crash don’t happen try to use soft reference and see if that works.