is attack on titan (shingeki no kyojin) episode 31 filler?

A steady rain begins to fall as the Scout Regiment regroups atop Wall Rose. An unconscious Ymir on a stretcher is carefully raised to the top of the Wall.

Eren asks about her condition, and Keiji informs him that her right limbs are missing and her internal organs are scrambled, injuries which would render a normal person dead. Eren helps Reiner reach the top of the Wall as Historia speaks with Section Commander Hange, insisting that Ymir is not a threat to humanity despite keeping her Titan powers hidden for so long.