Steps to reproduce:
1) Open project from attachment
2) Run it
3) Click on green box. It will start animating - from green to red and fully transparent.
4) When animated box will be almost transparent click on it once again.
5) Wait for all animations completed.
Green box should return to it's original state
Green box is semitransparent (depends on moment when you clicked second time)
You can watch attached video that demonstrates bug.