I'm unable to reach Age 4 as Egypt in this quest(regular one, part of the Assist Persia questline), building the Temple of Ptah does nothing, the civ remains in Age 3. Not sure if it's a one off bug as i only have one Egyptian civ(and eles rule, even in age 3), naturally. I've finished this quest with Babs, Celts and Norse without encountering any issue reaching Age 4.