Progress Bar Flicker?

Sopanda

So I've had a progress bar to the scene which indicates how much towards a "bonus" the players get. When the player reaches the amount, a timer slowly decreases the size of it and then it resets and starts all over again. So when the progress bar is getting filled up at the start, there is no flicker, but when it drains itself and goes for the 2nd time, there is a flicker on the bottom. I had that problem in the beginning but i was fixed by a constrain rule which i have at the bottom of the rules, but even though i have put it at the bottom it still flickers.

The rule i have to control the progress bar:

Rule:

if game.2x is false - constrain attrubute self.size.height to max(0,min(game.multi*20,320)

if self.size.height = 320 - set game.2x to true

if game.2x is true - every .25 seconds - constrain attribute self.size.height to self.size.height - 10

if self.size.height = 0 - change attribute set game.2x to false , change attribute setg game.multi to 0

constrain attribute self.position y to 126+(self.size.height/2)