Xperia Z3 back cover elevated itself

[Pz3004]

So I have been using my Z3 for about a month now, I recently noticed that my phone doesn't lay flat on the ground, it wobbles a little, then it starts to worry me, under close inspection, the back panel between the power button and the microSD card slot was elevated up, I am really concerned about it, is it because the overheating of the phone? The adhesive is melted by the overheating of the phone? I am scared that the phone will loss its waterproof ability…

[Xperiaz3sony]

Almost Same problem is with me.
My xperia z3back cover got elevated itself and i am not able to findout the reason.
Service center checked and told me that to change backcover leave your mobile phone for 3-4days. Backcover will b available on order.
When i asked them what will b the cost for new one, as my ph is in warranty it will b free for me or not?
But they said no warranty for backcover and we dnt knw the cost when it will arrive we tell you its cost.
I asked what is the reason of loosing and elevation? They dont have any answer for that.. And above all after their inspection my phone is now little bit more elevated.
Now i m confused what to do . Service center dont know anything. they are not technicaly sound and trained to handle these types of phones.

[MarkMRL]

This happens because of a defective battery that will inflate. Should be covered under warranty. I had my Xperia S replaced under warranty a few years ago because of this. It's also a common problem on certain laptops.

[Ik23]

I have the same problem. About a month after buying my xperia I noticed that the cover glass is loose down on the left side. I've sent the device to my local xperia care service and I hope them to send me a new device. This is an absurd failure from a world brand like Sony and I think that they MUST do something about that. The customers can't be happy to face this kind of problem after paying 600-650€ for a smartphone.

[MarkMRL]

This kind of stuff can happen with batteries, both on cheap and expensive phones. It happened to my 1800€ macbook pro.