Mineshafts Not Generating Correctly

Mineshaft logs are not generated below mineshaft floor. Mineshaft also generates a floating floor, not connected to anything.

What I expected to happen was...:
Logs to generate under mineshaft floor and fully connected mineshaft floors.

What actually happened was...:
Logs are not generated under mineshaft, and mineshaft has a floating part, not connected to anything.

Steps to Reproduce:
1. Seed: 6837080607505635680
2. Go to cords, 44 -32 230