In case the title is a bit confusing:

Whenever I do a standing power attack with daggers, it looks like he starts doing a horizontal slash attack and then interrupts it halfway through with a top-down chop attack. Is this how it's supposed to look? I ask because I used to get a bug that looked similar with the Deadly Reflex mod for Oblivion.

PS: I do not have any mods installed except a few texture packs and some ini tweaks.