Check closely deep down into the whirl and you may find what's eating it, usually a caterpillar of some type, looks like some "frass" / poop is present, best guess.

I am finding some gunk on the leaves as I look closer, thank you much appreciated!

Hadn't heard of four sisters. Just FYI, sunflowers are somewhat allelopathic, so planting them next to something you want might not be smart. In fact, they are even self-allelopathic, and don't much like to be planted right next to each other. But they can keep the weeds down!

I have found little worm/Caterpillars in the whirls and I'll need to look into managing the pests better, I appreciate the tips! the sunflowers were optional, (traditionally its 3 sisters corn bean squash) but I figure the best way to learn is to do and learn from both my failures and from my successes !

I appreciate the information!

Sorry:: It appears you have a major European corn borer attack., https://extension.entm.purdue.edu/fieldcropsipm/insects/euro-cornborer.php . Not much you can do with infected plants. Only thing I have found to work to protect the healthy plants is a contact insecticide applied to the whorl.