Post process material doesn't blend

I’ve set a post process volume to blend but I can’t get a post process material to also blend as the player enters the volume. How can I blend a material along with the other post process settings?

What do yoi mean? PP material appears instantly?

Hi redbox - yes, I have two pp volumes, both with the same pp material. I’ve set the larger volume to unbound, priority 0 and weight 1, and the smaller volume to priority 1, radius 300 and weight 1. The effect is immediate when I enter the radius of the smaller volume though.