Humidity cracks often go through post positions or metal inserts.
There is one rare situation which can also cause cracks on posts. When the instrument is exposed to extreme heat, such as inside a car, the metal can expand while the wood remains in its original dimension. This can also result in cracks at the posts. Always be sure to keep your instrument inside the cabin if you drive in extreme weather.
Dont get the instrument pinned under any circumstances!!! (Read also: Crack pinning )