Maybe Japanese pair too noisy with high frequency shouting after each point make them can't concentrate. Before they serve also shouting

Seems like no motivation.

Japanese pair like already know what Malaysia gonna do and always one step ahead to the net or stay at back

Semi finalist and quarter finalist not same la. Who knows will lose at semi. What logic is this.

A lot forget that they already qualified from group of death and played 2 tough matches before this, and maybe to get the bronze is just a step too far. Like even LCW after defeating LD in semi, couldn't raise his game and body again against CL in final.
Not forgetting the Japanese are the higher ranked pair so it is expected that they will take the bronze.
I would say good job reaching semi finals, hopefully next Olympic go 1 step further.