Unable to add listings to existing markdown sale

I am having trouble adding listings to existing markdown sale promotions. Every time I go in to add listings to an existing markdown sale, after I select the listings to add the button to "save and review" just does not work. It only works if I create a brand new markdown sale promotion, but it won't let me add listings to existing ones. I contacted ebay via chat and was told to clear my browser cookies and cache. I did and it's still not working.