Home button getting hot

Hi guys.

I did look to see if anyone had had this issue with an iPhone 6 before the other thread i think they were referring to a 6S.

OK i have just had a phone come in for a screen repair their child had smashed it off a wall & the screen was shattered but also the home button had been torn off too.

I have replaced the screen but any home button it try gets so hot you can't touch it i have tried both genuine recycled from other iPhone 6 & i have also tried aftermarket brand new ones all with same result.

I have had this once before but it was my bad as i had used a 6S home button on a 6 & this got hot just the same as this one.

Any ideas please?

Thanks in advance.