More obit whacking. Turned out that there was an INHIBIT_MOVE cloging up the works. The following procedure got rid of the damned thing.

On each replica-containing server
SET DSTRACE=!D [disables DS-sync, but DS stays up]
SET DSTRACE=+obit [turns on obit tracking, used later]
DSREPAIR -OT -A [go into dsrepair]
Advanced -> Repair Databases -> Accept defaults
Wait until the Master is done

On the Master replica server:
SET DSTRACE=!E [enabled DS-sync again, and lets it do what needs doing]

At one minute intervals, SET DSTRACE=!E on the rest of the servers. Watch the obits flow.