Some poor workmanship + the expansive soils of Arkansas + a couple of very dry years + a very wet spring = lots of foundation movement.

Its a combination of all the above, along with some time thrown in. I've been seeing some of the same thing, mostly minor so far, but the conditions will most likely continue unless some action is taken. Deferred one that was a little worse than this to an SE, who basically told the client not to worry, it was as bad as it was going to get and that he didn't think that it was that bad.
Alton Darty