Car seat moves on its own accord

[johnny1962]

Has anyone else experienced this. Whilst driving to Scotland today, my wife started to move the passenger seat (angle of seat) back in reverse as though to go to sleep, then stopped as it was at the correct angle to doze off, the seat then started to reverse the angle and push her whole body down face almost between her legs and even though she tried to move the car seat back to the original position, it took a long time for it to move back again. Meanwhile I was traversing four lanes of motorway trying to bring the CSR to a stop. Is currently working fine but hat was frightening. Anyone else experienced anything lime this