Are you sure it wasn’t sorghum?
I am indeed a city boy, but I’ve hunted through hundreds of corn fields and yes, I do know the difference. This was in Nebraska, where corn is one of our major economic drivers and a major source of corn for the U.S.
Now, could the corn appear (“fill in”) later? Maybe. I don’t know, I suppose it’s possible, but I’ve never seen this happen. Two things I’m sure of: 1) The 2 farmers I met with are forecasting their corn yield this year to be zero, and planning to use their crop as sileage, whatever that is. 
2) There were no cobs on the stalks in most (all?) the fields we drove through last weekend.
Maybe this is not so uncommon? I thought it was strange to say the least.