Sometimes when the sugar glider is on your head you still take normal fall damage. When taken off there is a chance the effect stays at 0 seconds. This causes the player to fall slowly but still take normal fall damage.

Same exact thing here.
Although for me it isn't sometimes, but rather, consistently.
The effect does slow down your fall speed but once you land, you will recieve the same amount of damage as you would normally, depending on the height you jump off of.