Continuity mistake: When the ponies encounter the Manticore, it raises its paws and shows its undersides and Fluttershy notices something, even though nothing was there. Then when they stop attacking the Manticore, it shows its paw to Fluttershy to reveal a thorn, but the thorn wasn't there earlier. (00:05:25 - 00:06:20)
Continuity mistake: In the shot just before it goes back to Twilight and Cadence when they are about to escape, it shows Lyra Heartstrings in the crowd. When the shot does go back to Twilight and Cadence, it shows Lyra as a bridesmaid. Likewise, in part 1, Lyra is still a bridesmaid.