This error seems to be the exact opposite of what was just discovered and posted on eventhubs. going from standing to crouching to block gets you hit while crouching before the normal results in a whiff.[details=Spoiler]https://www.youtube.com/watch?v=CTY68e3mifA[/details]
someone posted the reason in the bug thread. it results from the crouching hitbox being used when transitioning from crouching to standing, so you only have a hitbox on poison’s upper body when doing this.