iPhone X acting up in warm/hot temperature

Recently my iPhone X started acting very strange. Firstly I have noticed that intermittently my phone touch screen starts pressing all over screen without me touching the screen (opening random apps, typing non-stop random things when keyboard is opened). After couple of days I have noticed that this kind of behavior starts when I get into a hot car and as soon as iPhone gets slightly warm, the strange behavior starts, when I cool down the iPhone by just sticking it out the window while driving it goes back to normal. So now I'm sure that warm/hot temperature makes the phone touch screen act up and it is impossible to use the phone.

Any idea what could be wrong? Phone has not been tempered with since factory other then Apple replacing rear camera 1 year ago. Acting up started couple weeks ago.

Thank you