is bleach episode 302 filler?

Ichigo asks Isshin Kurosaki what he meant by being able to teach him the Final Getsuga Tenshō here and Isshin explains about how the Dangai is an isolated space which is surrounded by numerous stacked-up layers of time's current, resulting in it being a place where the density of time within it is extremely high when compared to other exterior dimensions. Isshin tells a confused Ichigo that when 1 year passes outside the Dangai, 2,000 years will have passed in the Dangai.