Really hard to think of a reason why with so little information to work with.
Please do read through this post as I do see it is your first time posting in the forums and provide more information regarding your issue:
Things I can think of from the start is to check your version, I am running 8.3.0 and it is working correctly. You might even just need a reinstall of Katalon Studio.
Next is to see if this happens on a new project as well.
And another thing you can check is to see if this happens when you run the same project on a different machine.
Remember a computer has many variables that can cause the problems you are experiencing and it could also be caused by something else and not the Katalon software itself.