If it is a private server, I have seen another post from someone reporting that reducing damage from ‘friendly fire’ in the server settings was somehow impacting fall damage. I can’t recall exactly what they said (whether it was reducing fall damage instead of reducing friendly fire, or maybe was increasing fall damage inverse to friendly fire) - but that might give you a setting you could play with and try different options to see if it is affecting you.
Edit: found a related thread here
2nd Edit: Aha - this is the report I was remembering here