When simulating in Editor, the Skeletal Mesh bone locations are not being passed into simulate if the simulation is being toggled the same frame when the Mesh is being set on a Skeletal Mesh component.
This was reported and tested in 4.20.3 (CL-4369336). This was reproduced in 4.19.2 (CL-4033788), 4.21 (CL-4516095), and Main 4.22 (CL-4531805)
Results: Mesh's bones won't be updated with the correct locations and will have strange locations for one frame right after it is first rendered to the screen
Expected: Mesh's bones locations are being correctly refreshed before simulating physics and rendering to the screen
There's no existing public thread on this issue, so head over toAnswerHub just mention UE-66147 in the post.