This is a real issue, not a practical joke. I'll try to keep it concise. Whenever I use the /fill command as follows:
"/fill <x1> <y1> <z1> <x2> <y2> <z2> minecraft:deadbush"
The game crashes. Whenever you attempt to reenter the Minecraft world, the game crashes. I haven't the slightest idea why this only happens with deadbush.

Describe what you thought should happen here:
What I expected to happen was to simply have a bunch of deadbush in an area. I was experimenting with the /fill command, and, well...

Describe what happened here
The game crashed within seconds of me executing the command.I tried the same thing in different worlds to make sure it wasn't just a poor world save file.

Steps to Reproduce:
1. Enter a Minecraft world with cheats enabled.
2. Do "/fill <x1> <y1> <z1> <x2> <y2> <z2> minecraft:deadbush" Not sure what a minimum or maximum size would be, because I used guess and test.
3. Wait mere seconds for you're game to crash.
4.Should work about 95% of the time.

Thank you for putting this issue into consideration. Not sure if it is significant, but I appreciate it anyways.

Note: There are two crash reports from the two times I tried this.