Well it doesn't work. You play as a scoundrel and:
You use Vault and sometimes it puts you outside the backstab zone. This is understandable if there was no space behind the enemy but it does it anyway 50% of the time even if there is.
You attempt a backstab after a vault and then (somehow) this is taken as a shuffle outside the backstab zone before you even try. This takes 1AP.
This is even worse than Vault not working. You are already in place to make a backstab and the game decides you should wander elsewhere for 1AP so you can have a worse chance of hitting.
I save between every turn in case the game decides to do something odd like this.
It didn't do it in previous versions though.
