Does "married adults living with parents in parents' house" count as breaching the third precept?
I am confident that a married couple who live with their parents are not in violation of the precept against sexual misconduct. If anything the question would apply to the marriage decision (asking parents for consent), but certainly not sexual activity that happens after the marriage.

IMHO the point is that you need consent before having sex, and in the case of young people, you should not treat their own consent as acceptable because they are too young to decide, so any time you aren't sure, their parents should be involved in the decision. Honestly that sounds horrible either way, but we can imagine young people getting married and how the consent of parents would often be a factor in that union not being misconduct, especially in an ancient society.