For what it's worth, had it happen on a small block once. After eating several distributor gears, we determined that the distributor shaft (on a purchased rebuilt distributor) had a slight bow in it. How or why or where the bow came from, we never figured out. We took the shaft out of the housing, put it in a lathe and put a dial indicator on it. And there was a slight in and out runout on the shaft. Wasn't enough to really see with the naked eye, but it was there. Replaced the distributor and never had another problem.
Would be odd you've run it for 2000 miles, and then something like this just show up though. Just speculation on my part.......................
