Steps to reproduce

• Open a creative world (this can also be reproduced in multiplayer or with commands)
• Type /achievement give achievement.acquireIron (as thats the achievement before DIAMONDS)
• Get a diamond block and craft it to get 9 diamonds, put those diamonds in your inventory
• Repeat this on a separate world but this time try smelting diamond ore to acquire the diamond

(Basically the bug here is that you can only get the achievement can only be obtained when the diamond is picked up from the floor rather than transferred directly into the inventory, something that doesn't seem to apply to any other resources (e.g. logs, iron...) )