Exactly what happened to mines one day, one of the rear abs sensors died, the plug in part, although the hub with that section of abs sensor was all okay, so was a relatively easy fix in my case.

But I did see a B class owner go through having to replace the hub as the sensor on that section had crumbled away.

 

The same happened to me, it was happening a lot and the code reader identified front left and back left abs sensors. I waited before getting them changed but before I did change them it one day just stopped haven’t had it come back in 6 months (touch wood)