confirmed for 1.9.2
I don't think this should be considered as a bug. This is implemented so that this doesn't work when you jump.
The game only increases the stat:
1) When your velocity on Y is negative after you've jumped AND your landing position is at least 1 block lower than where you jumped off.
2) When you take fall damage.
When you just walk off a block, it doesn't increase the score and maybe that could be added, but the name of the score is FallOneCm, not wentDownOneCm so this is probably right.
Lag is not a bug! Go to https://help.mojang.com/
You forgot that you have to use the enchantment id's, not the name. It works when you type:
/give xX_Eman_Xx diamond_sword 1 0 {ench:[{id:17,lvl:100}]}
So no worries! XD
Can you explane how you did this? For me it is not working and everything seems normal.
Important note: the AreaEffectCloud DOES get teleported! It's just the hitbox that doesn't get updated. If you testforblock, it will give you the correct answer and if you kill it with a radius, it will still be correct. So the position variables change and most other commands executing of that AreaEffectCloud will still work.
I got the same problem but for me the game crashed if I went below
For more information about this bug: https://www.youtube.com/watch?v=pOV-08RHLlM (made by Tango Tek)