During the song 'Here's to Us' we can see one of Rachel's dads stand up to clap along but in the next shot he is sat down and is only just getting ready to stand.
Toward the end of the episode, Quinn texts Rachel to tell her that she is running home to get her bridesmaid dress and will be at the wedding soon. Rachel later texts her "HURRY", which is confirmed when Quinn hears her phone go off while she is driving and looks at it to see 1 new message. Just a couple minutes later, being told that they can't wait any longer, Rachel texts Quinn again to ask "WHERE ARE YOU??". The phone, however, erroneously shows the last message sent still being the one from Quinn about the bridesmaid dress.
There's a loose strand of hair on the left side of Joe's face that comes and goes during the God Squad meeting.
Karofsky (in the hospital) has no bruising on his neck.
When Finn and Rachel are about to get married, he says "Well, Miss Hudson-Berry, everybody is waiting" and extends his arm for her to take. When it flashes to a close up of Rachel, you see Finn's lips moving, but no audio is coming out.
During the performance 'What Doesn't Kill You (Stronger)' A camerawoman can be seen behind Santana.