As noted, the third hour of last Monday's WWE RAW drew just 4.051 after falling from 4.511 million viewers in the second hour. The final segment of that show featured Brie Bella and Stephanie McMahon building to their SummerSlam match.
On a recent episode of Wrestling Observer Radio, a fan asked if any blame was being put on Brie for the low number in the final hour. We don't have the RAW quarter-hour ratings yet but it's very possible that the final segment caused the big drop. It was said that likely no blame is being put on Brie because it's Stephanie's angle and that would mean blaming Stephanie also, which isn't going to happen.