The Ruling When a Woman Was Unaware of the Obligation of Zakāh on Dowry and Jewelry for Several Years

Answer—and Allah is the One who grants success: Nothing is required of her for the years that have passed, because the elapsed years are like lapse of time in disputed issues. And this is the school’s position, as in the marginalia to Sharḥ al-Azhār.
Source : Min Thimār al-ʿIlm wa al-Ḥikmah vol.1