is bleach episode 366 filler?

Both in their Bankai, Ichigo Kurosaki and Kūgo Ginjō continue to clash as the group of Shinigami watch from below. They begin to turn away and leave the scene, much to the distress of Lieutenant Rukia Kuchiki, who asks why they are leaving.

Captain Byakuya Kuchiki pauses and asks Rukia if she recalls the reason for their mission to the World of the Living. He thus reminds her that their true mission was to observe the decision that Ichigo made.

Captain Tōshirō Hitsugaya elaborates that the Gotei 13 had always known that once another Substitute Shinigami appeared, he would, sooner or later, be targeted by Kūgo.