1.8 hardcore on death world not deleted bug

so I was playing hardcore mod, and I died, and boom, you're dead, pls delete your world, I clicked delete, and I returned to title page, but when I open my single players world menu again, I could still see my hardcore world which I died 1 min ago. However when I go back in, the death screen is still here, and still says " you're dead" and "delete world"

One more weird thing is, I can't even delete that world even when I go to the single player menu and try to delete it, didn't work, so I just left it there...

One more one more weird stuff : I tried to open a new world after my hardcore death, and the dirt bedground disappeared, and my hardcore world death screen is the one which appear instead of that normal, dirt bedground. Ah pls fix cause this is creepy...