Bug in my button

Hi,

I have this button which tweens to a color when u rollover or release/press it, and tweens back to its original color when u rollout or press other buttons, much like a history button thing (not the one with back button).

But there is one bug, when i rollover it and rollout very fast, the button does not tween back from where it is, instead it jumps to the last frame and tween back from there =(… how do i solve this?

Please help as this is bugging me >_<’