is attack on titan (shingeki no kyojin) episode 36 filler?

Ymir escapes the Forest of Giant Trees carrying Historia in her Titan's mouth. When Ymir nears the edge of the forest, Reiner transforms into the Armored Titan and begins their escape.

Bertholdt carrying an unconscious Eren grapples onto the Armored Titan's back alongside Ymir's Titan. The others watch in disbelief as Eren is once again carried away by the Warriors, and Commander Erwin spots the Armored Titan's departure.

Immediately formulating a plan, Erwin rallies the Scouts, Garrison and Military Police into action, urging them to follow his lead with the pursuing Titans.