The bug

When a double chest is placed and both sides of the chest have a Lock tag, it stays locked. When one side is unlocked, the entire chest is still locked.

How to reproduce

1. Place down a double chest.
2. Run this command on both chests:

   /data merge block x y z {Lock:"Test"}
   

3. Try to open the chest (should be locked)
4. Run this command on ONE side of the double chest:

   /data merge block x y z {Lock:""}
   

5. Try to open the chest again (stays locked)