I've also seen this happen when I accedentally got too close to the escort, causing it to freak out and deviate from its scripted course. (By "freak out" I mean lead me through a minefield then crash into the shore.) So far, I don't think I've seen this happen when I stay a reasonable distance away.
Then again, I have seen this happen often enough that I'm guessing most of the German economy during this period in history was based on repairing all the DD's that grounded themselves...
