TPS4H160-Q1: TPS4H160-Q1 ST response time on overcurrent

Part Number: TPS4H160-Q1

Tool/software:

Hi TI teams: 

I meet a problem about /ST repsonse time.

In TPS4H160-Q1 datasheet, it reocrd the /ST will repsonse after current limit occur.

Is the current limit means the over current occur or thermal shutdown occur?

Following is my waveform and schematic,  I set the limit current to 0.3A by a 6Kohm resistor.

It seems the /ST repsonse after the current limited and the response time is much longer than 180us, do you have any idea about what factor will affect the response time?