Some owners of 2016-2022 Mazda CX-3, 2013-2022 CX-5 and 2017-2018 Mazda3 vehicles may complain about a tapping/knocking noise coming from the rear seat area after a fuel fill.
The concern will likely occur if the fuel tank is over-filled or filled normally in high ambient temperatures where the fuel may expand.
Explain to the customer that they must avoid trying to over-fill or top off” (re: trying to add more fuel after the fuel pump nozzle shuts off automatically).
Overfilling and resulting potential fuel leakage is a fire hazard as well.