The Aethermancer set (Hat, Robes, Leggings, and Boots) does not reduce fall damage whatsoever.

To reproduce:
Start a world (with cheats, to get the set faster).
Without wearing the set, fall from 8 blocks. You will lose two and a half hearts (5 damage).
While wearing the set, fall from 8 blocks. You will lose two and a half hearts (5 damage).

Intended behavior:
When falling with the Aethermancer Set equipped, fall damage should be "highly reduced".

Looks like a check added in the latest update cancel the damage tweaking when the damage is dealt by something not entity-related. Good catch, i'll try to release the hotfix today

Please try out the new update and let me know if the issue can be closed

The set now correctly reduces fall damage - thank you!