Cave vines can generate without a head in Floating Islands worlds

The bug

When using the Floating Islands world type and using the Lush Caves biome, cave vines can generate without a head (only a body) when they would generate below Y = -64.

How to reproduce

Create a world with the Floating Islands world type, with the Lush Caves biome.

Seed: 8783321023364128694
Coordinates: /execute in minecraft:overworld run tp @s -80.81 -65.32 280.86 249.25 -2.50