Corn as a foreshadowing?
On my 7th-ish re-read I noticed something about the mention of corn that made me wonder whether GRRM inserts it as a signal that the character is about to have their fate changed completely, and start on their true path of destiny.
Bran often feeds corn to the ravens atop the tower which he then gets thrown off, thus beginning his true purposeful journey.
Arya passes corn, wheat barley fields with Yoran and dines on roasted corn in the husk just before Lorche kills the band with Yoran
After reading the Why Bloodraven is not the Three-Eyed Crow thread, I started thinking about the corn references and remembering some old wordplay possibilities around crown / crone / corn and crow.
I think you may be onto something with this:
I think this is especially true if that character has a real or symbolic destiny as a king or queen. This is consistent with the Corn King allusion brought up by Ser Creighton, above, although the symbolism seems to go beyond that allusion.