When I logged onto my Minecraft world, I wanted to get rid of a wheat farm. (I was actually just on the game paused screen.) I started breaking the wheat, and they dropped. It corrected itself after I broke 2 wheat. Also, the default gamemode for the world was adventure, and I wasn't holding anything that could break wheat in adventure mode.
Unfortunately, at the time I took the screenshot, I had gotten rid of the wheat farm because I decided I didn't want it.
Please provide a screenshot of the area with the F3 debug screen enabled.