The jurist’s axiom concerning water accidentally entering the body cavity during purification is that water which inadvertently goes down from something which is requested by the Sacred Law, even a sunna, does not invalidate the fast and water that goes down from something which is not requested does.1
Washing the ears along with the face is sunna, so this water should not break the fast. And Allah knows best and he alone gives success (tawfiq).
1. Muhammad Shatta, I’anah al-Talibin (Beirut, Dar al-Fikr, 1998), 2:367.
Answered by Shaykh Abdul-Karim Yahya, SunniPath Academy Teacher