Prior to RAW, when the company did a cut live from the Verizon Center, Michael Cole mentioned that RAW would be live in moments, and that "former UFC Heavyweight Champion Brock Lesnar" was in attendance.
During RAW, Cole mentioned his UFC past once again. At this time, it is unknown what led to the policy change.
In the past, the UFC and WWE have worked together in regards to Brock Lesnar. When the UFC was originally pushing Lesnar, WWE allowed them to use footage of Lesnar from his WWE run. The UFC also gave the WWE no problems when game developers wanted Lesnar in the WWE 12 video game.