When Dexter looks up Holly Benson's address, the building number is listed as 622. However, when he arrives at the house, it bears a four digit number ending in "918" (the first number is obscured by the angle of the camera).
When Travis goes to Gellar's blog and reads the message that Dexter left him, he responds back by posting "To the False Prophet...you're not fooling anyone...", but when Dexter checks the blog while at the church, the message now says "False Prophet...I listened to you once and I made a mistake. But never again--I'm going to fix it".
The make and model of the boat listed when Dexter is looking it up at the Marina is listed as a Kia Sportage, which is a car.
When Deborah Morgan finds the card from Sol's Flower Shop, there is a disposable coffee cup sitting on her desk. The design indicates that it is a Peet's Coffee and Tea large cup. Peet's does not (as of December 2011) have any stores located in Florida, so it's unlikely that Deb would have a large disposable cup sitting around her office.
Peter Grant's address (per the magazine which Dexter finds in Holly's apartment) is in Coral Gables, Florida. However, the zip code given is 33104, which is a zip code for Miami Lakes, a town about eighteen miles north of Coral Gables.
Deb phones a flower shop to find out who sent flowers to a dead hooker. No shop owner will simply hand out customer data on the phone like that, just because the person on the phone claims to be police. At the very least, they would hang up and call back into the precinct to make sure they are actually speaking to law enforcement and not some illicit caller.