Smooth interpolation for display entities

Why does merging a item displays data to this {item:{id:"minecraft:diamond",Count:1s},interpolation_duration:20,start_interpolation:0,transformation:[1.000f, 0.000f, 0.000f,0.000f,0.000f, 1.000f, 0.000f,-0.200f,0.000f, 0.000f, 1.000f,0.000f,0.000f, 0.000f, 0.000f,1.000f]} not animate smoothly but instead