When Archie is telling Nate about when he first met Parker, they walk down a couple of steps before a flashback begins. After the ice cream flashback ends, Nate and Archie descend the same steps, again.
Dr. Hannity mentions that she has a PhD in Agronomy from Stanford. However, Stanford University doesn't offer any doctoral (or any degree, for that matter) programs in Agronomy.
The Steranko System blocked all cell calls, but Parker was able to reach Hardison on his cell while he was in the building.