When the sisters go to the mausoleum and Phoebe gets married in it's chapel. Leo says "we are all here", but they all forget Victor the dad is missing.
When Phoebe claps, after Paige uses the spell to get rid of Phoebe's zits, in the mirror behind her, Phoebe's body is turned facing the mirror, and her reflection does not move.
Cole puts Paige to sleep while she is still working on making Phoebe's wedding dress the right size, yet when they wake up in the morning the dress is finished.
Just after Phoebe attempts to marry Cole, a boom mic is visible for multiple frames. This happens when the whole family are talking at the church after the wedding has been ruined, just after Piper calls to cancel the catering company. Every time the camera cuts to Phoebe and Cole are talking, a black boom mic with a white tip can be seen at the bottom of the screen moving to capture each persons voice. It drops off-screen as Cole begins to walk down the stairs.
When the Seer and the Dark Priest are in the crypt together, the shadow of the boom mic is visible on the wall.
Paige is worried when she does a tarot card reading about Phoebe and Cole and the despair and death cards turn up. The cards are meant to be symbolic, and the death card simply means change is coming. If Paige was actually into tarot as she appears to be, she would know this.
The preacher at the wedding rudely interrupts the string quartet in the middle of the Bridal Chorus, just to ask the congregation to sit down.