Collecting 2 items at a time by mistake.

I have a very simple game where the goal is to collect 15 stars. Everything works fine except that some of the stars count for 2 points instead of 1. I tried deleting the stars that get counted twice, but it changes every time. If I play it, a star will be counted once, then the next time I play it, maybe that star gets counted as 2 points. Its very random and I dont know why its happening. I only want each star to be worth 1 point.