Problem with summoner DPS pet issue.

[Kevee]

you do not need a parser to test this out.

Goto any training dummy, or mob. Set your pet to 'Obey' (this will mean it only casts its primary 3s cd nuke, and nothing else unless it has a autoattack like Ifrit/Titan appears to).
Click over to your 'Battle' log, and you can see each hit damage
Garuda 100 potency hits for me for 190 each attack
Ifrit 120 potency hits for me for 130 attack
the numbers may differ for you, but this is my results at lvl 50 with relic and some mixed gear.

higher potency skill, less damage. Is there some sort of inner scaling that we do not know about?

No one knows if it's a bug or not, but I'm guessing it isn't because Ifrit would do more raw DPS than Garuda if his attack was used on CD properly.

My idea is that it may be Ifrit scaling off the physical damage of books, whereas Garuda scales off the magical damage. It would make sense, since Ifrit needs DK for more damage, while Garuda needs FR. The numbers are similar enough that this is my best guess. Garuda does roughly the same damage as ifrit when switching to a book of electrum, which has 46 magic damage(relic+1 has 46 physical damage).