Sometimes, updates break things. That seems to be the case for some HTC owners who, upon receiving a silent update to the newest version of Google Play Services, are having trouble using apps that rely on location data. According to HTC phone users in this support thread, Google Now continually asks to turn Location Services on, location-dependent applications like Foursquare and WeatherBug don't function properly, and Maps is unable to lock onto a location.
The good news? Google's looking into the problem. The bad news? No ETA. And unfortunately, because Google Play Services updates in the background automatically, wiping data won't help.