Forge version: whatever version the modpack is on.
Twilight Forest version: 4.0.655
Link to crash log: (please use a paste site such as gist, do not attach the .txt or paste the log inline)

Steps to reproduce: go to the coordinates provided on the seed provided. and find the hollow hill
1.

What I expected to happen: for the hollow hill to have generated normal

What happened instead: for the stalactites to be above the ground level

the robust tree glitch is also at this location

Fixed via b098ddc