From what I see, the onChange() event handler only triggers when one of the suggestions is selected. However, it seems to me that onCustomValidation() is probably a better way to go.
Note, that onCustomValidation() is a function and not a property. You can set it in the page’s onReady() function, like this:
$w.onReady(function () {
$w("#addressInput1").onCustomValidation((value, reject) => {
console.log('customvalidation value', value);
// do your validation here
});
});
You can do your validation in this function, which will also take care of displaying a validation error message, etc. See Velo: About Validating User Input with Code and the Custom Validations example for more information.