Ignore, is a duplicate - Ocean Monument dissapeared after update to 14w26c

I had logged out in an Ocean Monument and when I logged back in after an update to 14w26c from 14w26b the structure of the monument had disappeared, replaced by air blocks.

I had built a safe platform at sea level out of some mined prismarine and that has disappeared too.

I still have all the prismarine/sea lanterns/sponges etc in my inventory.