1.Create a new world
2.Finish loading the world
3.Turn of your device and turn it on again
Observed Results:

Some times, weird textures appears in the game. Default texture pack. 

Expected Results:

The world will be weird. Torches appears as grass and crying obsidian appears as crimson nylium.

Only this world was affected and once you close the minecraft and open it again, it will disappear.