Night of the Sentinels: Part 1 - S1-E1
Continuity mistake: When the Sentinel is resting against the building while lying in wait for Jubilee, the building itself has a solid exterior with the occasional window. When the shot changes, it is now a glass building. Additionally, when the Sentinel was resting against the building, its entire body was obscured, but when the shot changes, part of the right side of its body was sticking out. (00:14:35)