Thanks for your contribution. If I understood the cause of the cracking, I wouldn't be canvassing fellow owners for their experiences. The unit has not been banged or bumped. Based on the lack of an apparent cause, and the outcome of the 'poll', my suspicion is that there is an inherent fault in the units. This may be design, material selection, manufacturing or a combination thereof. Given that it took 30 months for the issue to manifest in my case, it may be an age related problem. The implication, if this is correct, is that other owners may have this issue to deal with, and that, if it is inherent and unresolved, then it will continue to 'dog' the model (and the brand) in future iterations.