On the latest snapshot (14w04b), my giant map made of smaller maps and item frames fell off the wall:
This is happening to all item frames across the map.
What is causing this, and how do I prevent it from happening again? (Also, these all turned to stone entities when I reloaded the save).
Best Answer
There was a bug in a recent pre-release that caused item frames to fall off.
I'd highly recommend that you do not use your normal world when testing pre-release versions. Use a temporary world for that purpose, as it is likely that bugs like this will creep in from time to time, some more severe than others.