I have this same issue. In my case, I have two properties. One property (primary) has a mortgage, the other does not. In the past, I was able to make a second entry under "property taxes" for the taxes paid on the property on which I do not have a mortgage. This year, I only get the message that I've maxed out my $10K SALT limit. I do not have the option to enter property taxes for another property. As a fix, I can go into the Schedule A and manually enter the tax on line 2C. Although it's not needed for the federal return, it makes a difference on my state tax.
