Warped dues to heat buildup

So I was at work yesterday night and I placed my phone face down on a counter. I then noticed that it was warped. The phone has never been in a tight pocket or abused in any way. Never dropped either. I had it on my night stand last night and when I woke up 7 hours later the battery was down to 25% from 100%. Three-step no new apps that have been installed do I can rule that out. Has anyone had any similar experiences with warping? I am going to contact Asus tomorrow, because it should not be warped so soon. I have only had it 5 weeks. None of my other phones have warped.

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