It’s my understanding that someone at GM did a Rule 0, #1 no-no in engineering a product; that is, they changed part of something with no ECO (engineering change order) that would have to be signed off on by lots of people. In fact, they changed the very design, VERY bad.
The mfg company that I worked for many years ago was so tight on this that someone could get fired for sneaking in a change of an approved supplier of a common screw that had no apparent affect on safety, never mind something like the above.
I read sometime back that the plunger was lengthened that fits in the detent which holds the rotating housing in position, by lengthening it it increased the spring tension.
They didn’t change the part assembly number and they didn’t recall the cars that had the old parts. This was in late 2005 so they had tons of cars on the road for years with the problem.
Heads should roll if that’s precisely what happened.