Particles that are spawned using the surface of a static mesh will be offset from the systems placement in the world unless it is at world origin.
Working as expected in 4.19 CL# 4033788
Found in 4.20 Preview 1 CL# 4112139, and 4.21 CL# 4118128
This is a regression.
Results:
The particles will spawn offset from system unless it is at world origin
Expected:
The particles will spawn properly from where the Niagara system is placed.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-60245 in the post.