I am new to UE spent sometime searching for the solution myself, posting this for anyone wandering why the Niagara System’s Location is not changing even after specifying the Location in the “SpawnSystemAtLocation()”. Please follow the below steps:
- Open your Niagara System.
- Click on Properties on the Overview Node.
- In the right pane, check the Local Space option. (Reference Image below)
Now your Niagara System should spawn at location specified in SpawnSystemAtLocation() function.
Feel free to add/correct me if I am wrong, I am comparatively new as well 
Reference Image:
