Cigar Shaped UFO from today's photo & document release at National Archives

[ArMaP]

of course that could be their intentions, or it could just be bureaucratic inefficiency

The power of bureaucracy is very strong, in all official places, so I wouldn't be surprised if it takes a large part of responsibility for this mess.

But, having said the above, I know personally that organising archives is not an easy task. As the only way of being sure of a document's content is to read it, many people rely on the previous classification or assume it's the same as the other documents on the same group (I don't remember the right name at the moment).