Maddie tells Gibbs she and Kelly buried a suitcase but Gibbs digs up a lunchbox.
In the beginning scenes when Tony first jumps into the water to save Maddie and Gibbs, he breaks and removes the windshield and removes Maddie from the car. When he comes back down for Gibbs, the gunshot-riddled windshield is back in place.
When Gibbs digs up the "time capsule" there is quite a lot of dirt attached to the roots. When he finds the box, it's about 2 inches deep. The plant could not have come out of that hole. In addition, since the box was so shallowly buried, it would have been uncovered when the garden was planted.
Tony breaks the windshield of the car at the start of the episode but when when Gibbs is trying to get out of the car the windshield is still on.
When Abby took picture of Gibbs and Maddie, they were walking side-by-side. However, in the photo that Abby gave him, Maddy was in front of and closer to Gibbs.
Obvious CGI or video compositing when the car goes off the dock and splashes into the water.
At 37:20, as Ziva gets out of the car to question the mail man, she approaches him under a sign for the National Register of Historic Places, for the North University Park District, which is in Los Angeles. This makes it clear that they are not in DC.
When Kelly and Maddie were friends, Gibbs lived at Camp Pendleton.
In this episode, while living in D.C., Gibbs digs up the time capsule / suitcase / lunchbox in his backyard.
However, Kelly and Maddie never lived in D.C.