Minecart with tnt explodes when any type of minecart is pushed into it.

What I Expected to Happen
The minecart and minecart with tnt bump around and basicly do nothing.

What Really Happened
The minecart with tnt exploded

How to Reproduce
1. Make a 2x2 rail pattern (in picture)
2. Place a minecart of any kind and a minecart with tnt down on the rail.
3. Push the minecarts together and an explosion happens.