Items In Containers Get Removed when switching to 1.7.4 from 14w03b

All blocks and items in a container in a map gets deleted (even blocks in inventory) when switching from 14w03b to Minecraft 1.7.

Containers include:
Dispensers
Item Frames
Inventory
Minecart with Chest
Chest
Hoppers
Droppers
and probably other containers.