Information regarding this is available at Photocritic International written by A.D. Coleman and it is a big sorry mess.
There seem to be many misconceptions about this situation.
The holders (not owners) of this collection were not ordered to sell by anyone, they sought permission to sell and the court order involved allows them to do so.
The great majority of the images apparently were on permanent loan to Polaroid with the express proviso that they should be available to the artist for reproduction and/or exhibition.
There is a huge, so far unexplained, descrepency between the 24,000 works that Polaroid claimed for many years to have and the 16,000 that are now claimed.
I would strongly recommend to anyone interested in this story to read Mr. Coleman on the subject.