The Case of the Capricious Corpse - S6-E2
Revealing mistake: The murder victim is seen through the legs of a chair - just as the scene changes he blinks. (00:11:00)
Perry Mason (1957)
1 revealing mistake in season 6
Starring: Raymond Burr, Barbara Hale, Ray Collins, William Hopper
The Case of the Lucky Loser - S2-E2
Visible crew/equipment: After leaving her husband at train station, Harriet takes a cab to meet a man at a cabin. After a few mins, she takes the man's car to go home. As she drives away, there's a reflection of a man, in suit with glasses (possibly the director) standing offscreen. (00:05:20)
Hamilton Burger: Incompetent, irrelevant, and immaterial.