Plot hole: According to the family tree viewed in this episode, Penny "Grams" Halliwell was born on 6/23/1937, and her daughter Patty, the Charmed Ones' mother, was born on 4/5/1950. In addition, Patty's father was born in 1930. So, according to this, Penny gave birth to her daughter at age 12, while married to a 20 year old man. That's quite outlandish, to say the least. (00:20:05)
Continuity mistake: On 2/17/1999, Phoebe realizes that her past self, P. Russell, died on that same date in 1924, and was the same age as Phoebe is now. According to the family tree she is looking at, P. Russell was born on 7/2/1894, meaning that she was 29 upon her death. But Phoebe was born on 11/2/1975, according to that same family tree, making her only 23 at the time of this episode. (00:20:25)
Continuity mistake: In the scene when Phoebe and Leo return to the rest home, after she has changed places with old Phoebe, when Antoine places the amulet on her, he doesn't clasp it behind her neck, he just lays it on her. When she sits up, it doesn't fall off.
Continuity mistake: The family tree shows that Grams died in 1968 but the sisters were all born in the1970's. Didn't Grams raise the girls after Patty died in 1978?
Continuity mistake: In the teaser, when Phoebe physically experiences a past memory, the left strap of her bra is pulled off her shoulder. She then collapses to the ground. When her sisters find her the bra strap is back up on her shoulder. (00:03:25)
Continuity mistake: Leo says that Piper's past lover is his past life. If it was a past life, in 1924, that means Leo must have died almost straight away to be old enough to qualify as a doctor in WW2. And it wouldn't be his past life but his own past if it was the same life from before he became a Whitelighter. But then he'd also have been 15-20 years older before he died in WW2.
Continuity mistake: When Phoebe is attacked by Anton's spirit, she puts her right hand over her throat twice. (00:03:15)
Plot hole: It is stated Leo is born on May 6th, 1924. Yet he was in his 20's as Piper's ex-lover in his past life around 1924. It also stated that that is when he died and became a whitelighter but the war wasn't until 1942. He died shortly after that meaning he didn't become a whitelighter until after 1942.
