Q: Are fuel injector banks and catalyst converters considered different issues and warranties?

I recently had a check engine light come on and took my car into the shop for repair at a chevy dealership. They diagnosed a fuel injector bank issue and charged over $1,000.00 parts and labor for repair. The same check engine light came on a couple of months later, and this time they diagnosed a catalyst converter problem and want to charge another $1,000 in parts and labor, claiming it is a different issue, not covered under the warranty for the other part replaced. Can you confirm if this is accurate?

My car has 80000 miles.
My car has an automatic transmission.