TOPIC: Can't Make Changes to Fee Fields

I have a maddening problem with my event registration where people register and periodically, it shows that they are free registrants, when they are not supposed to be. They aren't entering a discount code, so I have no idea how it is coming up with free. It works most of the time, but sometimes it gives away $395 conference registrations and I have to contact people to let them know that they are not free.

So I decided to comb through all of the fields and make sure there's no some hidden fee field that is messing me up. I had a field that I was using early on where you could declare that you were a presenter and get a free registration. That field is now a hidden field that defaults to not being a presenter.

When I try to edit it to make it no longer be a fee field, save it, and reload it, the changes I make don't stick.

Same with any field that has a fee attached. Edit, Save, Open, and the changes are not saved.