Lee Rosenbaum issues "a major correction" regarding the transfer of the Brooklyn Museum's costume collection to the Met a couple of years ago. I wrote about the deal here. (See also here.)
Perhaps it wasn't what it initially seemed, but so long as any sales proceeds aren't used for operating expenses, it shouldn't be controversial under the Standard View on deaccessioning.
From my point of view, it's just another example of how the hypocrisy built into that Standard View -- sales to buy more art, totally fine; sales for any other reason, repulsive -- leads people to do a lot of funny things.