Guys, guys, I have a theory.
I think the attack animations glitch has something to do with the chat.
I've noticed, ever since I started playing, that the glitch doesn't seem to happen UNLESS I've been using the chat. Both the old chatbox and the new chatbox. So for the animations to work again, I have to log out, turn off the game, turn it back on, DO NOT USE THE CHAT, GO STRAIGHT INTO A FIGHT, finish up the fight and then the animations will work for the rest of the time I'm on game until I log out or refresh.
I don't understand what the chat has to do with the attack animations, but that seems to be what's been happening for me and for other people. Maybe someone tech-savvy could explain the reason behind it all.