The citation format in Zotero notes is currently just a default APA-style placeholder. We'll make this configurable in a future version, but currently the intended workflow is that you insert those notes into your word processor using the Add Note button of the word processor plugin, and the citations will be inserted in the style you've chosen for the document, as if you had used Add/Edit Citation.

https://www.zotero.org/blog/zotero-6/#adding_notes_to_word_processors