Not sure if this is a known bug or a new one but there seems to be a bug with date type questions when the field name is "Date" and you want to make the field not editable in a webmap. What I am seeing is the edit check box under configure popup is defaulted to editable but is grayed out so you cannot change it. You can uncheck Display but it still shows up as editable in the webmaps popup and in collector. This does not seem to happen if i name the field name is anything other than "Date". I have attached a survey excel file that i used to test this one. So far I've only seen this with the date type question.