That may be a glitch with the sign I didn't know you could get them in buy mode I have had my sim make them by clicking on the prom category that pops up after prom is announced so they put it in their inventory on their own. It is possible if you use the buy mode one together that might cause an issue unless they don't all get down on one knee. I haven't been invited to prom yet but I have more saves with teens to wait and see. I have been asked out though maybe it depends on how close you are, can't wait to see that.
