The contact owns a 2016 Mercedes GLE350 with a Nuna Car Seat installed, Model Name: Rava, Model Number: CS05107RFD, Manufactured Date: May 05, 2021. The contact stated that on several occasions whenever the harness was tugged on, the harness failed to restrain the child seated in the child seat. The manufacturer was notified of the failure and advised the contact that the kits to clean the release button on the bottom of the car seat would be released soon. The car seat was not replaced.