Inventory is lost and Player data reset

When moving my server over from 14w08a to 14w10b, all players inventories and positions were reset.

What I expected to happen was...:
Update to the new snapshot and keep my inventory and coords.

What actually happened was...:
Sent back to spawn and my inventory reset.

Steps to Reproduce:
1. Have server in 14w08a
2. Get something in inventory and move to a new position
3. Switch server to 14w10b
4. Load at spawn with no inventory.