I see this sort of thing on a fairly regular basis ... and I don't think the problem is caused by having the current 'pass through' the receptacle.
Sure, there's heat damage ... but I think we have to look deeper for the cause. Loose screws are always a likely suspect. For that matter, so are loose fitting plugs, partially inserted plugs, and some internal fault with the receptacle. Since everything is copper, heat will readily travel all over the insides.
