Samantha's Wedding Present - S5-E1
Other mistake: When Darrin is first shrunk we see that his clothes are unaffected by Endora's spell (they don't shrink). So, when he was popped back to normal heights, his clothes shouldn't be affected, and he would burst out of them. We already know his suit changed colors.
Samantha Goes South for a Spell - S5-E2
Other mistake: Serena tells Darrin that Samantha won't know him back in the 19th century New Orleans because she hadn't been born yet. In Aunt Clara's Victoria Victory, we know Samantha was alive in the 19th century because she and Endora were "in Tibet at the time."
Samantha Goes South for a Spell - S5-E2
Other mistake: Darrin doesn't recognise Serena posing as Samantha. We know from "That Was No Chick, That Was My Wife" that he can tell the difference. This happens in several episodes.
Other mistake: Samantha is reading a 4-line note from Endora. The paper is semi-transparent and in a shot from the front, we can easily see the writing through the paper. However, after the note is "twitched" into a second, shorter note, there's another shot from the front - and the lettering looks exactly the same as it did before. (00:16:40)
Answer: The original diamond and white gold heart necklace was given to Elizabeth Montgomery by her then real-life husband, William Asher, who also directed the show. She wore it in nearly every early episode. When the necklace was lost or stolen about mid-way through the series, Montgomery had two replicas made from rhinestones. She wore either one of those for the rest of the show's run.
raywest ★