I've this problem with my Pure White Arc S.A crack near the proximity sensor on the left side and two cracks near the volume button on the side of phone.I own this phone since two months later and have no accidents like falling etc...
I think this happens because of expansion and condensation.
I've contacted SE Belgium through facebook and they told me the crack is in fact a crack in the paint and doesn't affect the phone's safety...
Mine has also been sent for repair... still waiting though. Hope it's fixed permanently..
i have exact the same problem without dropping my phone -.- .
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