On breaking a Minecart with Tank that's been placed in the world, it will drop an empty Minecart and a Chunk Loader block instead.
I don't exactly have a way to show any great example of this, but just ran into the issue now.

Oh whoops, that's a pretty big issue. I'm going to look into this.

Fixed in the new patch. Sorry about that, not sure how that slipped through testing.