I once did a mileage run where we flew the same plane from pt A to B to C. I was in an aisle seat pt B to C and the same plane C to B. The seat would recline when we took off. The flight attend would come over after take off and demand I return the seat in the full upright position. I told her it was defective.

On the outbound flight. On the return flight I told FA. She did not believe me, but told me to just take another seat. When I moved the person in the middle took the seat. At first the seat was fine. Sure enough after takeoff, the seat started to recline.