Selling Egg Matzah - Yechaveh Daat 1:10

Rav Yosef deals with the issue of whether a Sephardi, who has no issue with egg matzah, is allowed to sell such matzot to an Ashkenazi. He begins by reviewing the basics of the egg matzah issue, including whether or not adding fruit juice to the mix speeds up the chametz process or permanently impedes it. He then presents the fact that Sephardim are lenient on this issue while Ashkenazim are strict, although they will allow the ill and elderly to eat such matzot. In terms of selling, Rav Yosef writes that a Sephardi who is selling egg matzot must inform an Ashkenazi that that is what they are, since one is not allowed to mislead someone about something that that person is strict. However, Rav Yosef does limit the merchant's responsibility in this case insofar as he notes that if it is clearly posted in the store that these are egg matzot, then one does not have to stop the Ashkenazi from buying it, as he can assume that he is buying it for permitted purposes.