Factual error: There is a periodic table shown in the background of the lab, showing an accurate periodic table as of now. During 1945, at least 21 elements had not been discovered. (00:17:40)
Factual error: The Marine Colonel in Supergirl played by Eddie McClintock spends all of his time wearing Marine Officer's Dress Blue Bravos. Marine Dress Blues are ceremonial uniforms. On rare occasions, the Charlies or Deltas (no coat) may be worn as a work uniforms (the primary exception to this rareness being recruiters). The full uniform is certainly not worn for day to day work in the field.
Factual error: 1-1 A couple of spelling errors. A "community center" in Ceylon, a British colony, using the American instead of the British spelling. And Columbo listed as the capital of Ceylon; it's Colombo.
Factual error: At an eating area, a collector shows a man a computer screen with his daughter in real time and has her call him. She then speaks in the phone and you can see her lips and actions lining up perfectly with the words he is hearing. It would not be this perfectly in sink even in the most optimal of conditions. There is a slight delay between the video from the camera and sending that to the computer being shown. And then there is also a slight delay of the phone single traveling through one phone to the other. These would not line up right and so the father would not see the lips moving exactly with what he hears his daughter saying over the phone.
Factual error: The Coppa Italia trophy raised by the winning team at the end of the episode looks nothing like the real one. (00:21:00)
A.K.A Customer Service is Standing By - S3-E4
Factual error: Trish knocks the bad guy into the pool - he sinks to the bottom where Erik can conveniently grab the knife and cut himself free. But bodies don't sink - he should be floating on the surface, still out of reach.