What you need to do is look at live data for the ABS.
Check the wheel speed readings on all 4 corners . As you slow down look for the one that zeroes before the rest, in other words one wheel will not register when the others are all reading the same.
It is common for a ABS car to do this.
Also remember that default minimum speed reading is like 3 MH.
One of the sensors is dropping the signal at low speed, like 7 or 8 miles an hour.It will be easy to spot on the live data
Fact is stranger than Fiction