In episode 'Siren Song' (#5.4) Phoebe and Piper "orbs" to another location. Piper stands to the left of Phoebe grabbing onto her arm, when they re-materialize they've switched places.
When the demonic healer pulls a pole out of the siren, the pole is only blood-stained in the area that was inside her body even though the rest of the pole jutting out of her back passed through her body when it was pulled out as well.
When Paige and Piper orb out to find Melissa, they start bouncing ideas off of each other on how best to approach her. Piper tries to encourage Paige to tap into her inner Whitelighter, by reminding her that her "...birth father was half-Whitelighter." This is incorrect, as Paige's biological father Sam was pure Whitelighter.