Everything flickers when exposed to block light sources

According to MC-276807, lower light levels making everything flicker should have been fixed in 24w39a. This is, however, not the case when using block light sources.

Steps to reproduce (a video is attached):

1. Go into an area with light level 0.
2. Place a torch.
3. Look closely at the ground.
4. Everything flickers subtly.

Note that the part in MC-276807 that refers to everything flickering at night (skylight issue) no longer occurs, but the rest still does.