Combos miss (without it being Dodge or "miss") as the opposing player or mob just is not there. To be able to hit player agin, even if he is targeted, you have to break combo and step away.
Happens very much more often now after latest patches.
This often happens when character's face and body r facing another direction then legs.
First I noticed this in TL 1.05 and they implemented the same in Live with latest patch.
It is very annoying to watch closely for your legs.