I've played a match with Nidalee mid and her couger form E (Swipe) sometimes doesn't do damage. I've noticed this particularly against minions, not so much against champions. I wouldn't exclude the latter, though. Just wanted to point that out.
100% of the time if your character is in motion (walking or pouncing) her E casts in the opposite direction of her model. So when you go to W,E clear a wave, her swipe happens behind her and it misses.
The only workaround right now is to mash S and cast it once you know you're not moving, which adds a half second delay to a combo. (Until riot hotfixes it).
