I am having the same issue not having changes I want to make being saved. I want to remove the "Date" column on the line items, and it does not go away after unchecking it. I tried editing the "Standard" form, creating a new form, no luck on either option. I'm using Google Chrome, and have cleared my cache and cookies, and tried in private browsing window as well. What now??
Edit to add: also tried to do this on Firefox, which has never been used. I'm on a Mac, is that the problem?