A woman sees a doctor wearing rubber gloves from her perspective, but he wears no gloves from his perspective (when he touches her face) and then gloves again from her perspective.
Viveca's nail polish changes color in closeups, from her usual pink to red.
On Viveca's office desk, Columbo's newspaper and manila envelope keep changing position, disappearing and reappearing.
Shirley Blaine's obituary lists her as "Shirley Blane," while she is otherwise credited as "Shirley Blaine."
The opening scene makes no sense, scientifically speaking:
1) Research is done on animals, not directly on people (although final stage testing, is, in fact, done on humans);
2) Scraping the outer layer of dead skin won't help predict what happens to the inner layers;
3) The sampling in done on cheeks but it should be done on a different, less visible, area of the body;
4) It is done in an operating theater, for no apparent reason;
5) The doctor should then be wearing a mask to avoid contaminating the samples with his own bacteria;
6) Gloves would be a minimum to wear in that setting;
7) Sampling older women would make more sense than sampling young women if the aim is to show the effect of the cream.
Viveca's beauty mark is originally on her right cheek, but it switches back and forth between her left and right cheeks several times in the first few minutes of the movie. She later explains to Columbo that it's a fake one that she applies with an eyebrow pencil, but does not always use it.
Near the end of the episode, the door of the safe is ajar before Viveca turns the dial to "unlock" it; She also only slightly turns the dial one time instead of entering a proper 3-number combination.
When Columbo shows Viveca the newspaper with the news of Shirley Blane's death, the text in the section "Girl dies in automobile crash" is the same as in the section "Firemen praised for heroic deeds at annual dinner" with the paragraphs in a different order .
(at around 57 mins) Shirley Blaine drives off after briefly discussing prospective employment with Viveca Scott by the sea. A deep rumble can be heard, which is clearly that of a large car (probably with a V8 engine), but she's actually driving a compact 1971 Plymouth Cricket, which came with a small inline-4 engine with displacement no larger than only 1.8 liters.
After Karl arrives home, he looks into a microscope. There is a brief shot of the slide he's looking at and the microscope light is obviously on (otherwise he wouldn't be able to see the cells on the slide). He then hears a noise and goes to investigate, finding Viveca in the kitchen. Later, when Viveca grabs the microscope to hit Karl, she lifts it high over her head and hits Karl. The microscope has no cord, indicating that it had not been plugged in, so the light could not have been on.
The janitor does not empty the paper bin completely and tries to hide it from the audience by pushing the paper down instead of trying to empty it again (He just said how paramount it was to destroy all evidence of research to prevent competitors to lay their hands on it).
Obvious product placement of cigarettes: magazine advertisement on the female protagonist's lap.
Shirley, played by Sian Barbara Allen, is supposedly a chain smoker; however, she smokes like someone who is not a habitual smoker. She should have been directed to make the character look more accustomed to smoking.