Paper trading IOC orders

I submitted a number of IOC orders to the paper trading endpoint today. All should have been filled (limit price well above market price), but all were marked cancelled and were unfilled. For example, a limit buy order for 100 shares of AMD with a limit price of $60 was marked cancelled with 0 shares filled, even though AMD was trading at $56-58.

Is this a bug or does the paper trading API not have support for IOC orders?