As previously reported, the exact finish that was originally scripted for the Universal Title Match at WrestleMania between Brock Lesnar and Roman Reigns was supposed to be Roman Reigns pinning Brock Lesnar after bouncing off the ropes and hitting a fifth spear. Instead, it was changed to Brock Lesnar catching Roman Reigns off the ropes with a sixth F-5 for the pin.
It is unknown who exactly knew about the new finish to this match apart from Vince McMahon, Paul Heyman, Brock Lesnar and Roman Reigns (who was only told about the new finish on the day of the show). One guess would be that Triple H and a few other key people within Vince’s circle were likely informed about this new finish.
Referee Chad Patton was just told to count to three once Reigns’ shoulders were down. He wasn’t told in any specific way or terms when to count the three, meaning it was the wrestlers’ responsibility to get their shoulders up before the count of three as the referee would be counting anyway. Michael Hayes, who reportedly set up the match with the wrestlers and Paul Heyman was reportedly not told about the new finish so he laid the match out with the previously mentioned finish where Reigns would win via spear.
Source: Wrestling Observer Newsletter