WWE is a very large organization, and a lot of stuff happens backstage. Some of the bad things that happen backstage are leaked. Backstage brawls are actually quite common in the WWE, and wrestlers do get aggressive with the management as well. In fact, some wrestlers are known to be extremely hard to work with.
Being a former UFC Heavyweight Champion, Brock Lesnar is one of the best wrestlers currently signed with the WWE. He is the current WWE Universal Champion, and is paid really well, if a few reports are to be believed.
Lesnar isn’t really liked by his colleagues backstage. Some have stated in interviews that he gets the most out of the WWE. CM Punk, a former WWE wrestler, talked about how displeased he was with how WWE was handling Lesnar when Punk was still working for them during an interview with Colt Cabana.
During a special WWE24 on WrestleMania 34, Lesnar was seen walking angrily backstage. In the short clip, he threw the Universal Title in the direction of Vince McMahon, and McMahon was caught yelling at Lesnar as Lesnar was leaving the room. This obviously means that he was angry at the reaction he got from the crowd.
This also goes to show how tough things are backstage! It isn't easy to be the boss of a world reknowned wrestling promotion!