A button that can be click at first time, cannot be clicked second time. It seems to be not clickable.
This is not a bug in Katalon Studio (therefore I will move this discussion) it is a problem in your test.
To help us help you, follow this advice:
Hi Marco - are you attempting to click on one object or do you have multiple objects that are captured as the same thing? If it something along those lines then you need to either capture them individaully or manually input the xpath to identify them through location rather than attributes. That being said this is just a guess from your title. As Russ has said, please provide more info.