Font does not update via style customizer

Hello,

I have a template that is a single button for a numeric keypad I made. The button displays the current value of operator entered setpoints. I created a custom property called "fontSize" on the button which I binded to a template property (also called fontSize). I then use fontSize as the driving property in the style customizer to change the font. When I change the value of the template property in the designer on the template screen itself, the font size on the button text will change, however, when I create an instance of the template on a different designer screen, the binding does not change the font size.

Is there something I am missing here? Can clarify further or add pictures if needed.