Quote Originally Posted by Herby View Post
You spam-clicked the upgrade button too fast.

The system didn't recognize most of your clicks.

Do it one at a time.

If there's no system message, it isn't a true upgrade and won't take effect.
See that would be the case if i had more than 2 blue stars in my inventory. Besides spam clicking at a 20% success rate isn't logical nor is it necessary since you can't go below 4 stars once you achieve that.