According to Apple forum discussions and reports from tipsters, it appears that the sound is being caused by a loose battery. In one case, a user simply took her phone to the Apple Store, where a Genius reapplied adhesive to the battery and sent her away. Has anyone else experienced this problem?
When you have literally millions upon millions of iPhones being pushed out, even strict manufacturing tolerances can’t guarantee that every single unit will be flawless. But we’re keen to see how widespread the issue could be, so let us know in the comments if your iPhone 5 has been making weird noises. [Thanks Trevor!]