There is nothing technical about the ABS very simple system.
Sensors pick up rotational speed of all four wheels and if not all within set amount, open valves in abs valve unit to reduce pressure in that particualr circuit(wheel), (very simplified version).
They(abs) do have faults but I would suggest leaving it a while as with a worn bearing the wheel will have been trying to list/tilt, and in so doing would have imparted a side wear onto pad, which will wear off before too long, then they will sit perfectly flat against the disc again.
tabetha