Basically, currently, this is how it is:

Summon: Always shows icon of Emerald Carbuncle, even after you learn Garuda-Egi

Summon II: Always shows icon of Topaz Carbuncle, even after you learn Titan-Egi

Instead, it should be that once you learn Garuda-Egi, the icon for Summon should change to show Garuda-Egi. Same thing with Summon II and Titan Egi.