The original bug exists with a patch replacement sky. Meaning GZDoom is rather derpy with tall skies (skies over 128+ in height).
Transfered skies are now producing a new type of bug; most likely relating to the actual bug as seen above.

Might want to undo that original commit and see why GZDoom is going derpy when tall skies comes into play. Please note that tall skies can range from 128-256. Maybe even taller.