Ghost Blocks

Put the summary of the bug you're having here

What I expected to happen was...:
When i blew up some TNT, i thought that the blocks were going to be (really) blown up.
What actually happened was...:
I blew up the TNT, but when i try to walk in the place where the blown-up blocks were, they acted like ghost blocks aka it looked like it was destroyed but the blocks were still there (solid air or something like that)

Steps to Reproduce:
1. Get some TNT or a Creeper to blow up in a place where blocks surround you but have a doorhole.
2. Try to walk at the part where the TNT or Creeper exploded.
3. See that you can't move inside the place where the TNT/Creeper blew up.