When Jim starts the record player, it spins up to 33-1/3 RPM. The next time they show the record it's spinning at 78 RPM.
When the Petri dish is placed on the elevator by the robotic arm, it is off-center and hanging over the edge. In the next shot, it is perfectly centered.
Beck's résumé mentions four scientists: "Virchow, Kock, Chaveau, Pasteur". However, the second and the third names should be spelled Koch and Chauveau.
Rollin is posing as a prisoner being tested for a virus in a foreign country. During the experiment his heartbeat is monitored and the result printed on a paper by a computer. In two scenes on the paper can be read "Rockville Center, NY".
The sign on the listening booth door lists the Age Limit at +/- 18 yrs., using the plus sign over the minus sign notation.
Jim listens to the recording in a glass enclosed booth in a record shop. When the recording self destructs, the smoke would have been visible to others in the store. This would have attracted unwanted attention.
When Barbara Bain's character is sitting in her hotel room, the lamp next to her head is seen swinging. Several hours pass. She receives another call. She was still sitting in the same position---filmed from the back of her chair---and that lamp is still swinging! This was unlike Sutton Roley's perfectionism.
When the van, driving the prisoner to building 14, passes through the gate, a camera man, the camera and a man with sunglasses can be seen in the reflection of the drivers window.
The shadow of the boom can be seen in the upper right frame just after Capt. Olni enters Dr. Beck's office, when the doctor is meeting with Cinnamon.