1. Create world on seed -1890628709, survival, normal mode, including bonus chest and map, without caves & cliffs experimental mode enabled.  
2. Spawn is 104, 66, 4.  Chest with 4 torches generate next to player.
3. Create world on seed -189068709, survival, normal mode, including bonus chest and map, with caves & cliffs experimental mode enabled.
4. Spawn is at -32, 64, -32.  There is no bonus chest around the player.
5. Traveled to 104, 66, 4 to see if chest was at previous world spawn - it is not. 
6. Dug around the area and did not see the chest generating in any caves beneath the spawn point.
7. This seems to happen with other worlds on random seeds when created with caves and cliffs experimental mode enabled.

Expected Behavior:

A bonus chest should appear next to spawn when enabled with caves & cliffs experimental mode enabled.

Actual outcome:

No bonus chest appears next to spawn when enabled with caves & cliffs experimental mode enabled.