Falling Sand/Gravel Turns Dark

[MWisBest]

When sand or gravel fall, they turn a strange dark color, like what the wolves are doing in 1.0.0 when it's raining outside.

[TLUL]

Something similar happens to me in 1.2.5 where the gravel turns blue when it's falling. It's very inconsistent, though. Unpatching and repatching seems to fix it.