Very interesting article. Sounds like Stieglitz hadn't completely cleared the prints of ferrous oxide; and Steichen's treatment may have accomplished this but at expense of paper permanency.
I found this extract quite important regarding Stiechen’s treatment of the platinum/palladium prints.
' it appears that Steichen's treatment attacked the cellulose to some degree, disturbing the print's surface and weakening the paper support in some cases. This effect can be explained if a bleach was used to reduce yellowing, since bleach is known to degrade cellulose more than simple aqueous immersion (McCabe 1993).
Not good news for those who have invested large sums of money in the Steichen treated prints, the article also mentions the possibility that Stieglitz may have waxed his prints could have played a part in the initial yellowing of the prints.
I have heard that some of Irving Penn’s prints have started to deteriorate, however this has been found to be due to the 'Dupoint' glue that he used to attach the paper to the aluminium support before processing the print, rather than a problem with a platinum prints permanence.