We have the servers set for "safe teleporting". The problem often is that you will be teleporting before the chunk is fully loaded. Hence you fall in nothing until the chunk is made, then you are repositioned to a safe height, which may be above ground to where you are teleporting to. This will not always happen but does some. I never teleport to my bed on Sanctuary. It always sticks me on the roof above it.
If we turned safe teleporting off, you would die due to falling or be suffocated when the chunk forms around you.