iPhone 6 home button question

I have an iPhone 6 that I am replacing the screen on. I used a different screen that has a home button to test the phone and noticed that the phone refuses to boot up with the foreign home button attached. I unplugged it and it tuned on. I plugged it in and the phone shuts off and won't come on until the home button is unplugged. The original home button works fine and the phone will come on when its plugged in. Is this a new feature in iOS 10 and will it affect 3rd part replacement home buttons? (not touch iD function I know that won't work). If its not a new feature then what would cause it to happen?