That shows the config is indeed applied, it's configured that way, but the NIC refuses to use it for some reason. Not the first time I've seen that on a Realtek NIC, it's not very common, but some of those NICs cannot have their speed and duplex forced. The config setting applies, and the NIC refuses to use it. That's what you're seeing there. Is what you're plugged into really forced to 100 full? Best to always use autonegotiation if that's an option.