It's not that the animation isn't stopping, it's just that your logic is somehow flawed and sets it to the "walkL" and "walkR" animations again when it shouldn't. Maybe you need a variable to track the overlapped state. Bit vague sorry, but see if that triggers any thought processes I've added a few log messages to show this.
[attachment=1:1zg2vjnt][/attachment:1zg2vjnt]
Edit: ok, so I thought I'd have a good go at this as I might learn something. See the capx below. It seems to be doing what you want.
[attachment=0:1zg2vjnt][/attachment:1zg2vjnt]