The mummy mask and the erased inscription

Mummy mask from Saqqara

The mummy mask that all now agree was excavated at Saqqara once had a hieratic inscription on the (right) hand, a feature observed by Paul Barford back in March 2011 ("A question for St Louis"). Paul has an image from Goneim's 1956 publication that shows the inscription quite clearly. Yet this personal name has been erased as K.M. Johnston's recent photo of the mask shows.

I have now seen an image of the mask taken c. 1997 (or perhaps a little before) that shows that the inscription had been erased prior to acquisition by the St Louis Art Museum.

So when was this name removed? At what point in the collecting history?

And why would someone want to remove a personal name that would have identified the mask?

Curators at SLAM never seem to have addressed this significant (lost) detail.