I'd like to add to this.
Around the skel/zombies area, North of Southern Hills.
-Unable to mount my horse, the bar would go all the way up, but no horse. Only time I could successfully get back on the horse was when I waited like 25 seconds after engaging in combat (no, I was not under any 'spells').
-Mentioned before, but Mobs (in general, spiders/skel/zombies all types) in this area just kind of sit there. They may eventually group up and attack, but it is slow and really does do any damage. Soon as you get in and around the Whispering Woods, it seems to be better functioning.