Could be several things, but the wheel turn lock is the most common I've heard about.
Beats me whether this is a design flaw, a supplier flaw, or what? GM seems to have a problem with this happening. I actually take the extra step during parking to adjust my position so that my wheels are straight before turning vehicle off. Shouldn't have to do that, but I've heard enough stories like this not to take chances.
That said, it could also be a defective lock (more so than than the defect in design).
2008 Redline Auto