Yeah, Manchester United does have some internal problems but we have to consider them playing at home it is very difficult to beat Manchester at home, maybe you still remember when Manchester United played against Nottingham at that time they were 2 goals behind but managed to make a comeback 3-2 and win, it is proof that Manchester United has more strength when playing at home and that's why I'm not sure Brighton can win easily, the worst thing that can happen is a draw imo.
Manchester United not only have some internal problem but also they got bad news with several players injury after playing for their national teams, new signing Sofyan Amrabat got injury and seems he will not makes debut against Brighton Albion in this week. Beside with Raphael Varane still injury and actually will see Harry Maguire or Jonny Evans will play in the first minutes upcoming match. Internal problem face Manchester United I don't sure they keep strong although playing on their home, conceded many goals when playing home is bad reputation for Manchester United and homework for Erik ten Hag how to give three points against for Manchester United, but don't forget with another internal problem between Manchester United manager Erik ten Hag with Jadon Sancho.
If there's any internal problem at Manchester United, then it has to be the manager Erik Ten Hag's rift with their forward player Jadon Sancho which has made the club to order the England international not to train with the first team squad. Erik Ten Hag since his arrival has brought some kind of discipline at the club abd he started his disciplinary actions with the club's former talisman Cristiano Ronaldo which was one of the reasons that made the Portuguese superstar to leave the club.
It's a good development if you ask me because it's gonna make every member of that squad to always behave themselves as no one is exempted from being punished whenever he faulters.