Rain and snow can pass through untilted big dripleaf

The Bug

Precipitation (rain and snow), is able to pass through untilted big dripleaves.

Steps to Reproduce

1. Ensure that you're not in a warm biome.
2. Summon a large number of big dripleaves.

   /fill ~1 ~-1 ~1 ~5 ~-1 ~5 minecraft:dirt

   /fill ~1 ~ ~1 ~5 ~4 ~5 minecraft:big_dripleaf

3. Set the weather to "rain".
4. Look closely at the big dripleaves.
5. →  Notice how precipitation is able to pass through untilted big dripleaves.

Expected Behavior

The expected behavior would be that precipitation (rain and snow), is not able to pass through untilted big dripleaves.