Other mistake: When Elena is taken, Bonnie asks Jeremy for help. She says she needs his blood to cast a location spell to find Elena. But it doesn't make sense. Earlier it was revealed that Elena is adopted, so she and Jeremy don't share the same bloodline and cast could not work well.
Suggested correction: Elena was adopted by her uncle. Grayson Gilbert (her adoptive father) is John Gilbert's (her biological father) brother. Jeremy (Grayson's son) is actually her cousin, and related by blood.
Alterations - S1-E7
Other mistake: When Max drives Charmaine to the surgical clinic, watch the background. In the first few shots, they are driving through some sort-of suburban neighborhood if you look out the windows, but suddenly when the camera cuts outside of the car, they're in a parking lot for the clinic, nowhere near the neighborhood they were literally just driving through. There was no time-jump as they are having a continuous conversation through the entire scene.