That's not a Tia! (moonfire spoilers)

[Naria]

Or even if the little girl has both sunseeker and moonkeeper traits that doesn't mean that both her and her sire were not culturally sunseekers. F'lhaminn is a great example of this--phenotypically she is Moonkeeper but culturally she is a Sunseeker. Nor has there been any indication that she wasn't born into her Sunseeker tribe. Honestly, I just think that it was an oversight like Catapult suggested and the story was already written out when someone else was like "Miqo kid models are really cute, lets make them Miqo'te."