Radiant Shield is tracked correctly, its both in the combat logs and memory. It is also not a dot, and for those reasons I determine that radiant shield is very under whelming and doesn't work like we think it works.

For example, I haven't confirmed but it looks like any type of shield or ability that neglects dmg will also neglect the proc from radiant shield. Also, currently the way it is tracked in ACT, the damage reads out from the person it proced from... so if you look under outgoing dmg from the tank, you will see radiant shield.

There truly isn't a very viable spot to use ifrit over garuda other than preference to the user.