And if so, a link would be vunderbar.
My friend is claiming Rending Fury didn't used to have the "Once per round" limitation, but considering I never looked at the Feat until he mentioned it, I have no clue if he's right or if he just overlooked it until now.
The first printing said "once per round", so there has been no errata on that particular point.
Edit: I can't remember if Rending Fury was part of the Ultimate Combat playtest, but if it was, then the limitation may have been added after the playtest.
You easily tear your enemies limb from limb with your natural attacks.
Prerequisites: Base attack bonus +6, rend special attack.
Benefit: You deal rend damage if you hit with half the normal natural attacks your rend requires. For example, a troll that has this feat can rend when it hits with one claw attack, while a girallon that has this feat must hit one target with two claw attacks to rend. You can only make this rend attack once per round.
UC has not received errata yet due to not having a second printing so far. So it's always had the limitation.