normally when you close the receivers the BCG rear should push the buffer slightly into the buffer tube so that the buffer does not touch the buffer retainer.
sometimes dimensional creep/tolerance stackup (especially with parts from different manufacturers) causes the buffer the rest/impact on the buffer retainer during use. this manifests as a beat-up buffer and retaining pin (sometimes a broken retaining pin).
One possible solution is an Offset Buffer Retainer, basically a buffer retainer but the pin is moved forward slightly. This may be enough change so that the buffer will rest on the BCG and spare the retainer the beating. the retainer has a little shelf to interface with the buffer tube and help it stay in the forward position.
https://truenortharms.com/ar15_defau...-retainer.html