When the detectives and Officer Miller travel to Arizona to interrogate Tosca and Gearhardt, we are shown a police car driving down a sunlit desert highway. However, we are told in the voiceover that the flight landed at 1AM and they were met and driven to Cottonwood by Chief Snoddy. At that time, it should have been pitch black outside.
The receipt Friday finds in the back of the stolen car does not match the one he shows to Camille.
When Friday and Gannon are questioning Gearhardt, she shows them the ring she is wearing. But she has been in custody for some time and even a small town police department would inventory and hold such property, so she shouldn't still have the ring (or the glasses she is wearing).
When Friday and Gannon are interrogating Fred Tosca in Cottonwood, AZ, Tosca was rattling off state capitals. He said that the capital of Nevada was Reno. It's actually Carson City.
During the opening scene (pre-credits), Friday is on his way to lunch and leaves the office. As he does so, another officer sits down with Gannon and gives him his lunch in a brown bag. The opening credits play and when the scene fades back in, Gannon opens the lunch bag and the other officer picks up her apple. Friday then walks back in and starts some small talk with both. Friday never took a lunch then as no time had really passed before and after the credits. It appears Friday walked out of the office, waited a second or two and then walked back into the office.
When Friday and Gannon arrive at the apartments, we are told that it is a two-story building. However, when they start interviewing tenants, they talk to Ms Ridges in apartment 304--on the third floor. The killer had lived in apartment 302. As they're walking up the stairs to the third floor, another flight of stairs is visible above them; as they land on the third floor, Gannon looks up and to the right, in their direction.