What was supposed to happen:
Falling down on to the stone bricks, breaking blocks, commands, flying with no restrictions etc. Like normal Minecraft

What actually happened:
The character landed on barrier blocks, couldn't fly through windows, commands wouldn't work, escaping and quitting didn't work.

How to re-create the glitch.
1. Go on to LAN/server
2. Create a box/castle with holes in as shown in the screenshot(I've seen it with other builds as well, but his happens every single time you build it)
3. Disconnect
4. Reconnect
5. Break blocks on the ceiling
6. Double-tap space to fall.
7. Land on invisible barriers