I was worried I was the only one experiencing this problem, kinda hurts seeing your ranking get lower and lower with nothing you can do about it because you can’t complete the first mission since the fight won’t load, unlike some of the other players :(
It's possible the bug may have just been fixed. I'm not positive though. I had been unable to progress until just a few minutes ago. I did an arena fight then tried the event fight again and it worked perfectly fine this time. This is probably not a solution to the bug. This is just me notifying the community that it may have been fixed.