I just bend the foot of the figure, not the boot and it turns out fine. I have noticed that it happens sometimes with some shoes too. The problem is how the boot conforms to the figure I think. For example the boot doesn't always completely covers the foot. Part of the foot or the toes stick out, at first. Also, the boot is slightly twisted or offset from the foot. So I hide the foot and toes, and then use the figure's foot movement to pose the boot and it works great. I don't know about animations though, never tried that.