When running from the sinkhole, Izzy's prosthetic sleeve changes from black to gray.
When Gavin asks the scientist to carbon date his wife's wedding ring, they're forgetting that you can only carbon date something that was once alive. Carbon dating works off of measuring the amount of carbon 14, a radioactive element present in all living material, or material that was once alive. It does not work on inorganic items.
A ring buried in the ground for thousands of years would not come out looking shiny and new.
Teratornis (giant prehistoric birds-of-prey) skulls never possessed a crest on the top of their beaks in real-life. No fossil specimens display this physical feature.
In S02 E01, at 0:09:17.. 0:09:20, when Gavin is leaving the 2 girls for hunting, there's a wire mesh on the lower-right side of the screen.
They saw something packed in paper and tape in a car dickey and say this is heroin. There was nothing unique or branded or characteristic about the package. A common person who is not really dealing in heroin wouldn't recognize such a package. Even a regular heroin addict would not have seen such a large amount of packed heroin.