Related for Chullin 181:14

התראת ספק לא שמה התראה

R'Judah says: If simultaneously he is liable; if one after the other, he is not liable!<span class="x" onmousemove="('comment',' For the warning with regard to each one when taken separately is a dubious warning, which is no warning, hence he is not liable.');">⁹</span>

Maharam Schiff on Chullin