Do you get the same behavior if the media files are stored locally?
Jim -- yes, the same problem persists when I play locally. The glitching gets worse after a lot of back-and-fourth scrubbing too, then settles down if I park the play head for a few moments.
Have you got the latest BM diver, the one that came out last week?
Thanks for the suggestion. Updating to 9.6.6 did not solve the issue, but what did solve the problem was connecting the workstation to the internet and doing a comprehensive CS 6.0.3 update. Manually updating via USB stick did not work (update failed and reported that I was using counterfeit software -- a bug that adobe has since acklowledged).