Some, not all, mineshaft minecart chests duplicate after destroying.

If you destroy a minecart chest you clear, some will duplicate and you can get double the items.

I expect a minecart chest to drop its items when broken with a tool but the minechest stays intact and you can reopen it and get double the items. not such a bad thing but a bug nonetheless.

To Recreate:
1. Open a minecart chest in a mineshaft
2. Clear items
3. Close chest
4. Destroy minechest with a tool-Chest remains intact
5. Reopen minecart chest and obtain duplicate items
6. Re-destroy minecart chest and items will finally drop