-- In a follow-up to the already reported backstage incident between Brock Lesnar and Vince McMahon, the story remains that Lesnar threw the belt at Vince, but it missed and hit the wall instead. While some wondered if it was a way to work everyone backstage, Vince was reportedly not expecting it and Shane McMahon, who was beside Vince, definitely didn't expect it.
-- Lesnar and Paul Heyman kept walking to the back and they got in their SUV and were driven off. Shane, who didn't know anything, was said to be "furious" at what he thought was an attempt by Lesnar to intimidate his father and so he went after the two, but they were already long gone and there was no further confrontation. In fact, many believe that Lesnar didn't even know that Shane had come after him until much later when he was told by others who witnessed the entire incident.
-- Also for what it's worth, both Vince McMahon and Roman Reigns agreed to allow Brock Lesnar to give Roman Reigns the stiff elbow shots to the head in order to draw blood so that can be ruled out as being the reason for the confrontation.
Source: Wrestling Observer Newsletter. Subscription information & prices available at f4wonline.com