If it happens, something is broken or messed up. Should never reciprocate under any circumstances of proper function so that's news to me, so I just looked into it and it's only some early ones and apparently related to a roll pin error (either hole size or pin) on some of the first ones and should be replaced. If this is what's happening its not functioning as designed and should be fixed and thankfully it's an easy fix. Mine does have the marks but it's not from reciprocating it's from dropping the bolt. Looks like a super easy solution to a super minor % affected.
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