According to the comments (which we can't independently verify) this is a problem with early cases from many popular manufacturers, including Diztronic, Cruzerlite, and Verus. Customers say that the manufactures are aware of the issue and are sending replacements. Of course, the hole is small enough that end users should be able to make their own modifications with a small drill or something similar.
Widespread problems like this probably come from a faulty engineering sample or dummy phone, which phone manufacturers often send to accessory makers even before the device is announced so that there's a decent selection of cases at launch. (This is a frequent source of leaks for gadget blogs.) It seems like the sample sent to these case makers was either incorrect or the final design of the phone was modified slightly before release. Either way, it's a costly and embarrassing mistake.