Plot hole: Throughout the series, it's established that good witches don't freeze. In this episode, however, Little Piper freezes Future Prue and Piper when they come back to the manor to "kidnap" their younger selves. Simply because the Charmed Ones reason that only one "set" of sisters (past/future) could have their powers doesn't mean that Future Prue, Piper and Phoebe aren't good witches. In other time-travel episodes, the sisters remain immune to freezing and are still able to say spells make potions, meaning they are still good witches. For example, in Season 8 "Forever Charmed," Piper and Leo go back to 1975 (the same time-period as this episode) using Coop's ring, trying to find when Phoebe is alive again. However, when a startled Patty tries to freeze them, only Leo freezes. Piper does not, though she likely cannot use her freezing/exploding power in this time.
Charmed (1998)
1 plot hole in That '70s Episode - chronological order
Be Careful What You Witch For - S2-E22
Plot hole: When teenage Prue has run away with the demon, and Phoebe and Piper find her in the park, teenage Prue is 'killed'. Her sisters drive her home to get Leo to heal her, but shouldn't they have just been able to call to Leo to orb to them when Prue was first hurt, and heal her in the park, and save driving back to the Manor, risking Prue dying?
Suggested correction: I see orbing to the park but he didn't heal her, she was already dead and he can't heal the dead, that's why the genie brought her back - that's what Phoebe wished for.
But if they would have called for him right away - he would have been able to heal her before she died. However at this point in time I don't think they knew how to call for him.
They did, they first tried it in the episode when Piper was sick with an exotic disease and dying in the hospital.
It bothers me that they never used it again until Season 4. When Prue was held by Abby, Leo could have helped if she called, and so many other times... so annoying.
Abbey was not a demon, so calling out for Leo would have been revealing magic exists, and we all know what happened at the end of season 3 with that.
Cole: Phoebe, I love you. I don't know what's going on but maybe I can help. Would you like me to kill someone for you?
Trivia: Holly Marie Combs's real life pregnancy with her son Finley Arthur Donoho was mirrored by Piper's pregnancy with Chris in this season.