Parity issue with MC-213798.

When you grow the cave vines to get glow berries at the head parts, you notice that it doesn't have the same light levels unless you grow another glow berries on the body parts of the cave vines.

Step to Reproduce
1. Place down cave vines from top to bottom
2. Place a light block with a light level of 14 from a few blocks away
3. Bone meal the bottom part of the cave vines to compare.
---> Light levels are different from what it is intended to, unless you grow the body part of the cave vines with glow berries.