Quote from Donna Cox Baker on February 12, 2019, 3:47 pm

Zotero currently puts "n.d." for "no date" in formatted citations, when it finds no value in the date field. This does not allow you to leave it blank because you have included the date elsewhere, like in the title. I will request that they put in a potential override value (like a space) that tells it not to force in the "n.d."