Could be a few things technically.
A fault with the ABS rings, though unlightly unless you are experiencing either warning lights or feedback through the brake pedal at low speed.
A problem with the ABS sensors which takes the reading from the rings.
A problem with the wiring, or something loose (have a check through the fuses for anything blown, though I dont know if that'll be a cause) .
Or the actual dials themselves have an intermittant fault, try doing the test where you tun on the ign (but dont start the car) while holding the trip button down for a few seconds the dials will do their sweep test. Check on here for the built in diagnostic test and see what codes it throws up.
Other than that, the best bet is to take it to renault and have them plug it in to see if there are any faults and their tech have a proper inspection. Proper pain in the bum these intermittant faults so I hope it turns out to be something simple.