"Direct" international flights (that have connections) NOT upgrade eligible

I am flying Delta flight 17 from ATL-LAX-SYD. There is a 3 hour layover in LAX with a change of planes and gates. I noticed my online profile said I was NOT upgrade eligible on the ATL-LAX segment. I figured this was just a mistake since this is clearly a domestic segment. I called Delta and they said there is no way for them to add me to the upgrade list for the ATL-LAX segment because the flight is "coded" as a direct ATL-SYD flight in the system (even though we change planes in LAX). The agent said this is a "known glitch" that Delta has no plans to fix and I could ask the agent in ATL if she might be able to add me to the upgrade list.

I'm sure the ATL-LAX upgrade list will be enormous anyway, but it just seems crazy that a computer glitch would prevent being added to the upgrade list on what is clearly a domestic flight.