Plot hole: The mother lets her daughter drive because she forgot her glasses inside the restaurant and cannot see to drive. This only makes sense as a means to move the plot forward because if she was still at the restaurant (which she would've had to be because she couldn't have driven elsewhere without her glasses) then she would've just gone back in to get them rather than let a 14 year old drive.
Revealing mistake: When Phoenix bursts into flames on stage during her concert, the burn proof suit the stunt person is wearing (dressed as Phoenix) can be seen (her legs are very thick and her knees have deep wrinkles as well as the suit hem at her ankles can be seen).
Other mistake: When Boa Vista and Wolfe find the blotch of red marker ink under the tape from the bat it's a solid big red blotch, they determine it was transfer from the killer's hand. Then they show Cody holding the bat and he only has a small red smear on his hand, not even close to the amount needed to leave that kind of stain on the tape.
Dude, Where's My Groom? - S8-E6
Visible crew/equipment: Horatio's body doubles face is seen for a split second during the helicopter landing, he has the wrong hair and nose to be Horatio. (00:41:15)
Bone Voyage - S8-E7
Continuity mistake: When Horatio notices the Band-Aid on Nathan Cole's finger, and Dr. Ray asks if they can get a warrant, Horatio's position changes between shots from facing Ray directly then has rotated position about 90° and is looking at Ray over his shoulder. (00:29:35)
Miami, We Have a Problem - S8-E15
Factual error: Ryan is stated to have a BS in organic chemistry, working on his Masters in Genetics when we first meet him. When Travers tells him the shuttle was leaking oxygen, Ryan corrects him and says "air", to which Travers has to correct him. ANY gen chem student learns that "air" is a mixture of oxygen, nitrogen, water, and a few other trace gases such as helium and methane. This is a pretty big blunder for someone who supposedly holds advanced degrees in Organic Chemistry and Genetics.
Delko for the Defense - S8-E11
Other mistake: Horatio: "Eric, the forensics expert cannot get cold feet." There was absolutely no reason for Eric to be nervous. IF he'd been a CSI all this time, he would be in court testifying about his evidence on a regular basis. CSIs ARE the forensics experts.
In the Wind - S8-E14
Continuity mistake: When Horatio leaves Dr. Bradstone's cell, after informing him that his wife was having an affair, Bradstone's arms change position back and forth from across his stomach to behind his head. (00:34:25)