Thanks for the information.
The ‘LOD’ settings don’t actually stop objects from spawning/updating, including particles from an emitter, it just stops the objects being rendered to the screen.
An easy way to see this is to open the Niagara Debugger, run the map with the emitter and move in and out of the LOD range.
eg. In range:
Out of range:
If you look into ‘scalibility’ I believe that will have the effect which you are looking for, similar to the FMOD stealing/virtualization system it can “cull” objects when out of range but also keep track of where they would be if in range.