Persian Cataphracts available too early?

[Redmeth]

I'm in 245 in my Sauromatae campaign and wile riding my horse archers merrily through the steppe when I encounter a small army of 3 units: persian cataphracts, noble persian cataphracts and elite persian cataphracts, unit names being: Zradha Pahlavans, Azad Asavaran and Grivpanvar.
My question is shouldn't there be some reforms for the Parthians? I mean the Grivpanvar do have "late" in their unit name.
I defeated them in melee but with heavy loses, I know it's normal for the arrows not to much if any damage taking into account their armor, but the Parthians seem to get them way too early, if i understand correctly they barely broke free from the Seleucids when the game starts, and "they are nomads but not for long"...

[Sarcasm]

Short answer: Their roster isn't complete yet. Well, not in your build anyway...*evil laughter*