Steps to reproduce

• type /give PlayerName 95 to get a locked chest
• these use the new 'missing texture' texture since 13w18a
• place it somewhere
• the way this worked for me was I changed dimension then returned (e.g. the Nether and back), but it also works sometimes when restarting a world, the locked chest block will not be there anymore, you can test this by walking into where it used to be