Phoebe says that she empathically senses 'a whole lot of rage' from Zachary. But in the next scene she says she 'didn't read any anger from him'. This is a direct contradiction, with no explanation given.
When Jason first found out about Phoebe being a witch, he exclaimed that she kept it from him for 15 months, which means they knew each other for at least that long, but at the start of this episode Piper says Wyatt isn't even a year old yet, despite the fact that when Phoebe first met Jason, she was showing photos of Wyatt to her coworkers.
When the students are all frozen in the conservatory, their positions keep changing every time we see them. Slick, for example, is standing on the right when Phoebe walks in, but when Leo orbs the students away he is standing on the left side.
When Piper's head is on the dresser in the manor her hair keeps changing positions. It goes from in front of her neck to off the side to back in front of her neck to back at her side.
When the sisters' heads are on the table at Magic School, a gap can be seen around Phoebe's head where she has stuck her head through a hole in the table.
When they put pipers head ontop of the fireplace. closeup shots of her head talking show her hair to the side revealing her neck. another angle shot with her hair placed differently and her hair keeps changing locations during the conversation.
Phoebe used her empathic powers to get a "reading" on Zachary, but it was not Zachary, it was an astral projection. Phoebe would not be able to empathically connect with an astral projection.
Sigmund comments on a levitating student while the sisters first walk through magic school. Sigmund was only a head inside of a bag, and wouldn't have been able to see the girl levitating, not to mention he wasn't even facing her direction.