Factual error: Calleigh Duquesne frequently wears completely inappropriate clothing throughout the whole series. She often wears blouses that are so low cut that the neckline is below the lower curve of her breasts. No officer of the court in the US would be allowed to dress this way. There is no grey area here, and this is not a character mistake - first time a CSI turned up at work dressed like that, she'd be sent home to change. Second time, she'd be on suspension until she agreed to change her dress standards. Also (and this regularly happens in CSI: NY as well) she is regularly wearing high heels - also a certain no-no for as CSI. Incidentally, male CSIs have equally strict dress standards.
Episode #9.1 - S9-E1
Factual error: There is a picture of a container ship with the caption "Lat 27.09 N Lon 5.2W" These coordinates are in the Sahara desert. (00:13:55)
Factual error: After the two women found out the guy was dead, there is a truck with the writing "K-9 Unit" on the front, but it is not backwards as it should be.