Despite offering a workaround, it wasn't an ideal solution. We're glad to report that as of this morning the issue has been resolved.
Michael Clewley, Head of Product Development at BlackBerry posted this on his BBM Channel:
A server that provides sensor calibration information to the phone was sending corrupt data that would affect the sensors on the phone. The issue was resolved at the server. Customers that are affected can simply restart their phone to resolve the problem.
See Michael Clewley's channel on BBM: C00014277