Just to add, received a user report of the Master machine not clearing the VFB to start another render after a render completes using DR - the VFB continues to show the rotating smiley, and the "Render" button is greyed out; however, all slave machines stop and are ready to re-render, auto save has saved the images, and CPU use is low, so it is not still rendering, just hasn't reset ready for a new render. The user has been closing and restarting Max to resolve.
Also, anyone having corrupt PNG format files on autosave? The user reported the same thing, only with PNGs - the autosaved ones for render passes are corrupt, but doing another "Save All" manually from the VFB gets correctly formatted PNGs.