Summary:
When I created a new world on Minecraft pocket edition 0.14.1 with the old world setting on, there was a major glitch where blocks loaded (sometimes block faces) loaded (apparently infinitely) beyond the invisible bedrock boundaries.

Interested, I attempted reproducing the effect multiple times. It worked both when the world was created in survival or creative modes, but the blocks disappeared when the game mode was switched. The glitch only spawns water and varying types of leave blocks. The water and leave blocks could also be removed by destroying them and with buckets.

To reproduce: Create a new world, but with world settings set to old instead of infinite or flat. (I noticed roughly a 75% success rate at reproducing this bug)