is attack on titan (shingeki no kyojin) episode 56 filler?

In a dream, Armin Arlelt hears Bertholdt Hoover sobbing and opens his eyes. He sits up and sees the head of the Colossal Titan looming over him, though the face is more skeletal than usual.

As Armin watches, the Colossal Titan sheds a tear. Armin wakes up on top of Wall Maria.

He finds Sasha Braus laid out beside him, severely injured. Armin asks what happened, since the last thing he remembers is Bertholdt's transformation, and Levi Ackermann has Eren Jaeger bring Armin up to speed.