WLTOYS A959 and K989 latency issue

Hi,
I have 2 WLTOYS cars, a A959 and a K989. Both share the same radio. When I bind them to my Jumper T8SG V2 plus with V202 protocol, it works perfectly with the K989, but I have almost 1 second of delay between the stick movement and the car reaction with the A959. Does anyone have any idea ?