Teknow is using r19. Whilst his scene works in r20, without caching the scene, it is not true in r19. When you don't cache you get no crown effect. The above by Martin explains why you do need to cache dynamics for final renders.
So the altered work flow for final renders with dynamics is to cache dynamics - it also reduces render times as well. Below is rendered on R19 (i changed the hdri between the two renders)