I had followed the steering issues a while ago, prior to this problem, but eventually stopped after finding mine was working file. Then, fast forward 2500 miles, and this happened. I tried going back through some but gave up due to the sheer number of steering posts.There are a lot of threads about steering problems on the forum. Have you searched for all of them to see if you can find a similarity?
It should be noted that this occurred 4 or 5 times, in quick succession, about 11 days ago and it has not re-occurred since.