Continuity: Once Edwina's soul has entered Terry Hoskins's body, it makes no sense that she would still have a British accent. Victoria Tennant masks her accent immediately after the event, but lapses back into it when she says, "I love it when you talk like a beer commercial."
Revealing mistakes: When Edwina (through Roger) declares that Terry needs a spanking and she happily consents, her derriere is already red from previous takes.