Property Tax (homestead-->rental)

My previous primary home converted to rental. The county still record it as primary and so I can save $500 a year on property tax. I found this mistake last year and called and faxed the county to let them correct it. It still shows as primary home in the tax record (I have two primary now). I want to know if this will be a trouble when I sell the house in the future. They may found that I didn't pay tax as rental property for many years. Or, I can get by with this.
I have the fax record that I sent to county to let them change to rental property.