St Louis Art Museum Mask: implications for Swiss dealer

I have noted earlier this week that the collecting history ("provenance") for the Egyptian mummy mask acquired by the St Louis Art Museum was seemingly flawed. It cannot have been given to the excavator (who died in 1959). It cannot have been in Brussels in 1952. It cannot have been in the "Kaloterna collection" in 1962. The reason for this is the apparently undisputed statement that the mask was known to be in Egypt in 1966 and recorded in Cairo.

The collecting history for the mask was allegedly supplied by the vendor, Phoenix Ancient Art. One of the owners of the gallery apparently supports the repatriation of antiquities to the country of origin. What was the basis for the mask's collecting history as supplied by Phoenix Ancient Art? Who created the collecting history?

It now appears that SLAM's due diligence process prior to the acquisition was flawed. The collecting history, as it was understood at the time of acquisition, no longer appears to be secure.

Will the director of SLAM, who is a member of the AAMD, make the appropriate professional and ethical response by opening up negotiations with the Egyptian authorities?