Factual error: Commander Garnett, previously the chief engineer, becomes executive officer and starts wearing the line officers' star above her rank rings. This does not happen. An engineer is not trained to command a ship.
In the Dark - S3-E7
Factual error: "When we reach the States you will be charged with War Crimes and prosecuted to the full extent of the law." Despite a lot of assumptions, the USA is the only major power to have opted out of this convention. You cannot be charged with "War Crimes" in the USA. (00:05:55)
Sea Change - S3-E8
Factual error: They have EOTech or similar holographic sights mounted on their rifles, but "scope in" with a night vision sniper rifle scope of some kind to take out the two targets. The EOTech holographic sights are not night vision, nor have the magnification and reticle that was used in the show. (00:17:50)