PPF, PP319, and PP4L's favorite question!

The Golden Chains of Zenobia, The Smashed Printing Plate of Frederick Douglass, The Missing Portrait of Hans Holbein, The Bonnet of Dolley Madison, The Good Luck Watch of Empress Eugenie, The Diary of Dr. Livingstone!
Funnily enough, it occurred once in S1, twice in S2, and three times in S3!