Light and non-light heightmaps can be wildly different due to early loading of light into global heightmaps

[NotStirred]

Whereas light heightmaps are loaded into the global heightmaps at FEATURES status, non-light heightmaps are loaded into global at promotion to LevelCube.
If some terrain is on the edge of your render distance (such as an island in a sky islands world) this would mean that the heightmaps could be very different.

Is this an issue? I'm not sure we should even do anything about this, thoughts?

[CursedFlames]

This could cause behavior such as getting rainfall in areas that don't have skylight, but I agree that it doesn't seem particularly problematic. Probably leave it as-is for now but keep this issue open until we get closer to release and see if any problems arise.