R Meir Rabi asked for mekoros. I suggest Yechaveh Daas 4:43 Although Chacham Ovadya is Meikel he does bring Rishonim who would hold its an Issur Derabonnon as in Pesach for 'off' Chametz. This is probably the place to look but I don't have the Sefer in front of me at the minute.