The Friendly Physician - S2-E29
Factual error: When the castaways are coming back to the island at the end, you can see some of the Los Angeles buildings in the background in the high camera angle.
Factual error: The portable radio is an AM band only, therefore there is no need for the external telescoping FM antenna.
Topsy-Turvy - S3-E10
Factual error: When looking at the machetes the headhunters had, you can see the molded plastic handles on them. The natives wouldn't have access to such things.
Chosen answer: It looks like a mistake to me I see it when the Professor is put into a trance, but it is not there later.
Bowling255 ★