My 1997 A8 has developed a problem. When braking to a standstill from low speed, the brake pad would judder (feels like ABS is activated, but should not under such mild braking) and then the ABS warning light comes on.

But after the stop the engine and re-start, there is no ABS warning light.

I've taken the car to the dealer for checking this, but they could found any fault.

What could be the cause of this ?