ARG was the only pollster to give Clinton a 38 point lead in South Carolina a few days ago. A bunch of polls have since come out showing her lead has dropped to about 18 points. This poll was such an outlier, that it had Clinton winning whites by 19 points. All the other polls had Sanders winning or tieing among whites.
ARG released a poll tonight, only 2 or 3 days later showing Clinton winning by 30 points. This would suggest that Sanders is gaining about 3 points a day on Clinton. Or perhaps they are just playing catchup.