INA199: INA199A1DCKR output timing delay occurs when load is only under 20ohm or so

Part Number:INA199

Hi Ti experts,

We're using INA199A1DCKR as our current sensing application on motor. 

Below is our schematic-

While we were using INA199A1DCKR measuring the voltage across shunt resistor on motor output pin from motor driver,

we found the output of INA199A1DCKR acts differently when the load impedance is different. 

Ch1 (Red) is the waveform of current clamp Hantek CC-650 (bandwidth 20kHz)

Ch2 (Yellow) is the waveform of INA199A1DCKR output 

At 60ohm, 100ohm - 

The output voltage waveform rising and falling timing are almost changing concurrently.

But when we changed the load down to 10ohm or 20ohm,

The output voltage waveform did rise simultaneously, but there's a timing delay 15~20us on the falling edge between 2 channels while we did not find this symptom when load is above 60ohm.

docs.google.com/.../edit

Would you kindly help us to investigate why there's such a timing delay between the current amplifier INA199A1DCKR output and measured current (by Current Clamp)?

Motor impedance is roughly between 10 to 20 ohm. So the nonlinearity happens for our application and it causes difficulty for firmware development.