I asked the question thinking of the scabbard weight ... if there is one present.

The scabard weights are variously shaped pieces of lead that are held in the bottom of the scabbard by the screws that also secure the lower scabbard fitting. At a point after RZM dagger production began, the weights we eliminated. You can usually tell just by hefting the scabbard. Sometimes they get loose and jam the blade.

The other possibility is that the scabbard has been switched and the throat is not wide enough because it was not filed during fitting. You should be able to see if it is catching.

Dave