Create Food, and a Bug That Was Not There

Create Food is done.

Then I lost two hours to a bug that was not a bug. The game kept telling me "only instants can be cast in response" when I was playing the first action of my first turn, in response to nothing at all.

The rule was right. The message was wrong - it fires on a condition that has nothing to do with responding. An error message that describes the wrong cause is worse than no message, because it sends you looking in the wrong place with confidence.