Character mistake: The math test Tina gets a D on has #5 marked wrong. However it is correct. (Additionally it seems improbable she would actually get #3 and #4 wrong since she obviously understood the concept of how to do the problem and only had a problem with the division for some reason, and these questions didn't require division).
Mystery on the Prarie - S3-E14
Character mistake: If Chris and Martin are creature experts, they would have already known the buffalo birds are nest parasites.